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STATE OF ILLINOIS 1968 

DEPARTMENT OF REGISTRATION AND EDUCATION 



Rock Ollandf Mo4i4fUuUUf QaUdJu^fuj^f 



J. £ Brueckmann 
R. B, Berg Strom 



REPORT OF INVESTIGATIONS 221 
ILLINOIS STATE GEOLOGICAL SURVEY 

URBANA, ILLINOIS 



PROPERTY OF 

DEPARTMENT OF FORESTS & WATERS 

DIVISION OF MINERALS 



Rack yMand, Mo^funo-utU^ Qcueiiun4f.y 
and fCewanee A^a, OUiHaii 



J. E. Srueckmann 
R. E. Berg Strom 



ILLINOIS STATE GEOLOGICAL SURVEY REPORT OF INVESTIGATIONS 221 

Urbana, Illinois 19^8 



STATE OF ILLINOIS 

DEPARTMENT OF REGISTRATION AND EDUCATION 



BOARD OF NATURAL RESOURCES 
AND CONSERVATION 

Hon. John C. Watson^ Chairman 

Laurence L. Sloss^ Ph.D., Geology 

Roger Adams^ Ph.D., D.Sc.^ LL.D., Chemistry 

Robert H. Anderson^ B.S., Engineering 

Thomas Park^ Ph.D.^ Biology 

Charles E. Olmsted^ Ph.D., Forestry 

Dean William L. Everitt^ E.E., Ph.D., D.Eng., 

University of Illinois 

President Delyte W. Morris^ Ph.D., 

Southern Illinois University 



STATE GEOLOGICAL SURVEY 

John G. Frye, Ph.D., D.Sg.^ Chiej 



Printed by Authority of State of Illinois, Ch. 127, IRS, Par. 5S.25. 



ILLINOIS STATE GEOLOGICAL SURVEY 



Urbana, Illinois FULL TIME STAFF 



R. J. Helfinstine^ M.S., 
Administrative Engineer 



John C. Fryb^ Ph.D., D.Sc, Chief 

Hubert E. Risser, Ph.D., Assistant Chief 

Helen E. McMorriSj Secretary to the Chief 



Velda a. Millard, Fiscal 
Assistant to the Chief 



GEOLOGICAL GROUP 



Jack A. Simon, M.S. 
M. L. Thompson, Ph.D., Principal Research Geologist 



Principal Geologist 

Frances H. Alsterlund, A.B. 



Research Assistant 



COAL 

Jack A. Simon, M.S., Acting Head 
William H. Smith, M.S., Geologist 
Kenneth E. Clegg, M.S., Associate Geologist 
Harold J. Gluskotbr, Ph.D., Associate Geologist 
M. E. Hopkins, Ph.D., Associate Geologist 
RussEL A. Peppers, Ph.D., Associate Geologist 
Frederick N. Murray, Ph.D., Asst. Geologist 

CLAY RESOURCES AND CLAY 
MINERAL TECHNOLOGY 

W. Arthur White, Ph.D., Geologist and Head 
Bruce F. Bohor, Ph.D., Associate Geologist 
Mary K. Kyriazis, Technical Assistant 

ENGINEERING GEOLOGY AND 
TOPOGRAPHIC MAPPING 

W. Calhoun Smith, Ph.D., Geologist in charge 
Paul B. DuMontelle, M.S., Assistant Geologist 
Patricia M. Moran, B.A., Research Assistant 

STRATIGRAPHY AND AREAL GEOLOGY 

H. B. Willman, Ph.D., Geologist and Head 
Blwood Atherton, Ph.D., Geologist 
T. C. BUSCHBACH, Ph.D., Geologist 
Charles Collinson, Ph.D., Geologist 
Herbert D. Glass, Ph.D., Geologist 
David H. Swann, Ph.D., Geologist 
Lois S. Kent, Ph.D., Associate Geologist 
Jerry A. Lineback, Ph.D., Associate Geologist 
Alan M. Jacobs, Ph.D., Assistant Geologist 
Susan R. Avcin, B.A., Research Assistant 
Robert W. Frame, Supervisory Technical Asst. 
J. Stanton Bonwell, Technical Assistant 
Dorothy H. Scoggin, Technical Assistant 
Joseph F. Howard, Assistant 



GROUND-WATER GEOLOGY AND 
GEOPHYSICAL EXPLORATION 

Robert E. Bergstrom, Ph.D., Geologist and 

Head 
Merlyn B. Buhle, M.S., Geologist 
James E. Hackett, Ph.D., Geologist 
John P. Kbmpton, Ph.D., Associate Geologist 
Keros Cartwright, M.S., Assistant Geologist 
Manoutchehr Heidari, M.S., Asst. Engineer 
Paul C. Heigold, M.S., Assistant Geophysicist 
George M. Hughes, Ph.D., Assistant Geologist 
Ronald A. Landon, M.S., Assistant Geologist 
Murray R. McComas, M.S., Assistant Geologist 
Kemal Piskin, M.S., Assistant Geologist 
Jean I. Larsen, M.A., Research Assistant 
Shirley A. Masters, B.S., Research Assistant 
Verena M. Colvin, Technical Assistant 
Charles R. Lund, Technical Assistant 



INDUSTRIAL MINERALS 

James C. Bradbury, Ph.D., Geologist in charge 
James W. Baxter, Ph.D., Associate Geologist 
Richard D. Harvey, Ph.D., Associate Geologist 

OIL AND GAS 

Donald C. Bond, Ph.D., Head 

Thomas F. Lawry, B.S., Associate Petroleum 

Engineer 
R. P. Mast, M.S., Associate Petroleum Engineer 
Wayne F. Meents, Associate Geological 

Engineer 
Hubert M. Bristol, M.S., Assistant Geologist 
Richard H. Howard, M.S., Assistant Geologist 
David L. Stevenson, M.S., Assistant Geologist 
Jacob Van Den Berg, M.S., Assistant Geologist 
Albert L. Meyers, B.S., Research Assistant 
Paula K. Giertz, Technical Assistant 



CHEMICAL GROUP 



Glenn C. Finger, Ph.D., Principal Chemist 
Ruth C. Lynge^ Technical Assistant Thelma J. Chapman, B.A., Technical Assistant 



ANALYTICAL CHEMISTRY 

Neil F. Shimp, Ph.D., Chemist and Head 
Ju ANITA Witters, M.S., Physicist 
William J. Armon, M.S., Associate Chemist 
Charles W. Bebler, M.A., Associate Chemist 
Rodney R. Ruch, Ph.D., Associate Chemist 
John A. Schleicher, B.S., Associate Chemist 
David B. Heck, B.S., Assistant Chemist 
Stephen M. Kim, B.A., Assistant Chemist 
John K. Kuhn, B.S., Assistant Chemist 
Paul E. Gardner, Technical Assistant 
George R. James, Technical Assistant 
Benjamin F. Manley, Technical Assistant 

PHYSICAL CHEMISTRY 

JosEPHUS Thomas, Jr., Ph.D., Chemist, Head 
Robert N. Leamnson, M.S., Research Assistant 

COAL CHEMISTRY 

G. Robert Yohe, Ph.D. 



Chemist and Head 



ORGANIC GEOCHEMISTRY 

G. C. Finger, Ph.D., Acting Head 

Donald R. Dickerson, Ph.D., Assoc. Chemist 

Richard H. Shiley, M.S., Assistant Chemist 

CHEMICAL ENGINEERING 

H. W. Jackman, M.S.E., Chemical Engineer and 

Head 
R. J. Helfinstine, M.S., Mechnical Engineer 
Henry P. Ehrlingbr III, M.S., Assoc. 

Minerals Engineer 
Michael L. Schroder, B.S., Assistant Minerals 

Engineer 
Lee D. Arnold, B.S., Assistant Engineer 
Larry R. Camp, B.S., Assistant Chemist 
Walter E. Cooper, Technical Assistant 
Robert M. Fairfield, Technical Assistant 
John P. McClellan, Technical Assistant 
Edward A. Schaede, Technical Assistant (on 

leave) 



MINERAL ECONOMICS GROUP 

Hubert E. Risser, Ph.D., Principal Mineral Economist 
W. Tj. Btjsch, A.B., Associate Mineral Economist Robert L. Major^ M.S., Assistant Mineral Economist 



ADMINISTRATIVE GROUP 



EDUCATIONAL EXTENSION 

David L. Reinbrtsbn^ A.M., Associate Geologist 

in charge 
George M. Wilson^ M.S., Geologist 
William E. Cotb^ M.S., Assistant Geologist 
Helen S. Johnston, B.S., Technical Assistant 
Myrna M. Killey, B.A., Technical Assistant 

PUBLICATIONS 

G. Robert Yohe, Ph.D., Coordinator 
Betty M. Lynch, B.Ed., Technical Editor 
Carol A. Brandt, B.A., Technical Editor 
Jane E. Busey, B.S., Assistant Technical Editor 
Marie L. Martin, Geologic Draftsman 
Marilyn Crawley, B.P.A., Assistant Geologic 

Draftsman 
Phyllis R. Peavy, B.S., Assistant Geologic 

Draftsman 
William Dale Farris, Research Associate 
Teresa L. Fisher, Technical Assistant 
Beulah M. Unfer, Technical Assistant 

LIBRARY 

LiIeselotte p. Haak, Geological Librarian 

MINERAL RESOURCE RECORDS 

Vivian Gordon, Head 

Hannah Kistler, Supervisory Technical Asst. 
Ruth S. Vail, B.S., Research Assistant 
Constance Armstrong, Technical Assistant 
Patsy Maginel, B.A., Technical Assistant 
Connie L. Maske, B.A., Technical Assistant 
Mary K. Reller, B.A., Technical Assistant 
Elizabeth Speer, Technical Assistant 

GENERAL SCIENTIFIC INFORMATION 

Peggy H. Schroeder, B.A., Research Assistant 
Jo Ann M. Getman, Technical Assistant 



FINANCIAL OFFICE 

Velda a, Millard, in charge 
Marjorie J. Hatch, Clerk IV 
Virginia C. Smith, B.S., Account Clerk 
Pauline Mitchell, Account Clerk 

TECHNICAL RECORDS 

Berenice Reed, Supervisory Tech. Assistant 

Miriam Hatch, Technical Assistant 

Hester L. Nesmith, B.S., Technical Assistant 

SPECIAL TECHNICAL SERVICES 

Glenn G. Poor, Research Assoc, (on leave) 
Merle Ridgley, Research Associate 
Gilbert L, Tinberg, Technical Assistant 
Wayne W. Nofftz, Supervisory Tech. Asst. 
Donovon M. Watkins, Technical Assistant 
Mary M. Sullivan, Supervisory Tech. Asst. 
Emily S. Kirk, Supervisory Technical Asst. 

CLERICAL SERVICES 

Nancy J. Hansen, Clerk-Stenographer II 
Hazel V. Orr, Clerk- Stenographer II 
Rosemary P. Scholl, Clerk-Stenographer II 
Jane C. Washburn, Clerk-Stenographer II 
Becky L. Carr, Clerk- Stenographer I 
Magdeline E. Hutchison, Clerk- Stenographer I 
Edna M. Yeargin, Clerk- Stenographer I 
Shirley L. Weathbrford, Key Punch Oper. II 
Judy E. Graner, Clerk-Typist II 
Linda D. Rentfrow, Clerk-Typist II 
Pauline F. Tate, Clerk-Typist II 
JoAnn L. Hayn, Clerk-Typist I 

AUTOMOTIVE SERVICE 

Robert O. Ellis, Garage Superintendent 
David B. Cooley, Automotive Mechanic 
James E. Taylor, Automotive Mechanic 



EMERITI 

M. M. Lbighton, Ph.D., D.Sc, Chief, Emeritus 
Arthur Bevan, Ph.D., D.Sc, Principal 

Geologist, Emeritus 
J. S. Machin, Ph.D., Principal Chemist, Emer. 
O. W. Rebs, Ph.D., Principal Research Chemist, 

Emeritus 
W- H. VosKUiL, Ph.D., Principal Mineral 

Economist, Emeritus 
G. H. Cady, Ph.D., Senior Geologist, Emeritus 

A. H. Bell, Ph.D., Geologist, Emeritus 
George E. Ekblaw, Ph.D., Geologist, Emeritus 
J. E. Lamar, B.S., Geologist, Emeritus 

R. J. Piersol, Ph.D., Physicist, Emeritus 
L. D. McViCKER, B.S., Chemist, Emeritus 
Enid Townley, M.S., Geologist, Emerita 
Lester L. Whiting, M.S., Geologist, Emeritus 

B. J. Greenwood, B.S., Mech. Engr., Emeritus 



SEPTEMBER 1, 1967 



RESEARCH AFFILIATES AND CONSULTANTS 

Richard C. Anderson, Ph.D., Augustana College 
W. P. Bradley, Ph.D., University of Texas 
Donald L. Graf, Ph.D., University of Minnesota 
Ralph E. Grim, Ph.D., University of Illinois 
S. E. Harris, Jr., Ph.D., Southern Illinois 

University 
Lyle D. McGinnis, Ph.D., Northern Illinois 

University 
I. Edgar Odom, Ph.D., Northern Illinois 

University 
T. K. Searight, Ph.D., Illinois State University 
Paul R. Shaffer, Ph.D., University of Illinois 
Harold R. Wanless, Ph.D., University of 

Illinois 
George W. White, Ph.D., University of Illinois 



Topographic mapping- in cooperation with the 
United States Geological Survey. 



CONTENTS 



Page 

Introduction 7 

Previous investigations 8 

Geography 9 

Physiography and drainage 9 

Climate 9 

Population 9 

Economy and natural resources 10 

Geology 11 

Stratigraphy of the bedrock 11 

Precambrian rocks 14 

Cambrian System 14 

Mt. Simon Sandstone 14 

Eau Claire Formation . 14 

Ironton-Galesville Sandstone 15 

Franconia Formation 15 

Potosi Dolomite and Eminence Formation 15 

Ordovician System , 19 

Prairie du Chien Group 19 

Ancell Group 19 

Platteville and Galena Groups 24 

Maquoketa Group 25 

Silurian and Devonian Systems 25 

Hunton Megagroup 25 

Devonian and Mississippian Systems 25 

Pennsylvanian System 27 

Structure of the bedrock 27 

Glacial geology and bedrock topography 29 

Ground water . 32 

Water pumpage 32 

Drift aquifers 34 

Shallow bedrock aquifers .-: 34 

Deep bedrock aquifers 38 

Dolomite aquifers 38 

Sandstone aquifers 38 

Glenwood-St. Peter Sandstone 39 

New Richmond, Eminence, Potosi, and Franconia 

Formations 39 

Ironton-Galesville Sandstone 40 

Mt. Simon Sandstone 40 



Page 

Recharge and ground-water movement 41 

Flow in the deep aquifers 42 

Ground-water conditions by county 43 

Henry County 43 

Knox County 44 

Mercer County 44 

Rock Island County 45 

Warren County 45 

Conclusions 46 

References 47 

Appendix 49 



ILLUSTRATIONS 

Figure Page 

1. Rock Island, Monmouth, Galesburg, and Kewanee area 8 

2. Principal geographic features of the area 11 

3. Geologic formations of the area 16 

4. Bedrock geologic map with selected subsurface geologic boundaries 18 

5. Cross section of formations, bedrock surface, and land surface 20 

6. Thickness of the Ironton-Galesville Sandstone 21 

7. Depth and elevation of the top of the Ironton-Galesville Sandstone .... 22 

8. Thickness of the interval between the top of the Glenwood-St. Peter 
Sandstone and the top of the Ironton-Galesville Sandstone 23 

9. Thickness of the Glenwood-St. Peter Sandstone 24 

10. Elevation of the top of the Glenwood-St. Peter Sandstone 26 

1 1 . Thickness of the Silurian-Devonian limestone and dolomite 28 

12. Bedrock valleys and major drift boundaries 31 

13. Thickness of drift 33 

14. Sand and gravel aquifers 36 



TABLES 

Table Page 

1. Population and water pumpage 10 

2. Municipal water supplies 12 

3. Economic data for the Rock Island, Monmouth, Galesburg, and Kewanee 
area 14 



Ground-Water Geology of the Rock Island, Monmouth, 
Galesburg, and Kewanee Area, Illinois 

John E. Brueckntantt and Robert E. Bergstrom 

ABSTRACT 

Ground water in the Rock Island, Monmouth, Galesburg, and Kewanee 
area, Illinois, is obtained from (1) sand and gravel aquifers within the glacial 
drift; (2) shallow bedrock aquifers that are primarily dolomite of the Niagaran 
Series (Silurian) and the Keokuk-Burlington Limestone (Mississippian); and (3) 
deep bedrock aquifers, primarily the Ordovician Ancell Group (Glenwood-St. 
Peter Sandstone) and the Cambrian Ironton-Galesville Sandstone. Most private 
water supplies are obtained from the shallow bedrock aquifers, whereas the 
larger municipal supplies generally are obtained from the deep bedrock aquifers. 
Sand and gravel aquifers are sparsely distributed in the area. 

The estimated total pumpage of ground water alone is 16,531,000 gallons 
per day for the area. This constitutes about 50 percent of the estimated total 
pumpage of both surface and ground water and serves about 63 percent of the 
population. 

Municipalities now using ground water can probably develop additional 
ground-water sources to meet increased demands in the future. 



INTRODUCTION 

The Rock Island, Monmouth, Galesburg, 
and Kewanee area is located in the north- 
ern part of western IlHnois (fig. 1 ) and in- 
cludes all of Henry, Knox, and Warren 
Counties and the eastern parts of Rock 
Island and Mercer Counties. The area is 
approximately 48 miles wide from east to 
west and 78 miles long. Farming predomi- 
nates in much of it, although the principal 



cities have large manufacturing industries. 
The area is well served by rail, highway, 
and river transportation. 

Surface water and ground water are used 
in approximately equal amounts. The Mis- 
sissippi River is the main source of surface 
water. Ground water provides many muni- 
cipal and industrial supplies and nearly all 
rural supplies. Out of a total population of 
slightly over 300,000 people, an estimated 
189,000 people (63 percent) use ground 



water. There has been an increasing de- 
mand for individual ground-water supplies 
for homes and small industries in formerly 
rural areas where public water supplies are 
not available. 

Water-yielding beds (aquifers) are pres- 
ent in the unconsolidated glacial drift and 
in the bedrock. The drift aquifers are de- 
posits of sand and gravel that range in size 
from thin lenses of sand within thick sec- 
tions of pebbly clay to thick beds of gravel. 
The bedrock formations include several 
aquifers. In certain parts of the area, water 
supplies can be obtained from comparative- 
ly shallow limestones and dolomites, and in 
most places water is obtainable from deep 
sandstones and dolomites. High minerali- 
zation of the ground water limits use of the 
deep aquifers in some localities. 

The study reported here was made to ob- 
tain information on the geologic framework 
that controls the occurrence, movement, 
and availability of ground water in the re- 
gion. Such information is necessary for solv- 
ing the practical problems of obtaining ade- 
quate supplies of ground water where they 
are needed, both in rural areas and in 
areas adjacent to the cities that are becom- 
ing urban. The stratigraphy of the bedrock, 
which contains the most widely used aqui- 
fers, has been emphasized in the study. 

Previous Investigations 

Previous investigations of the ground- 
water geology of the area were made by 
Thwaites (1927), Buhle (1935), and 
Bergstrom (1956). Geologic reports on 
several quadrangles (Udden, 1912; Savage, 
1922; Savage and Udden, 1922; Savage 
and Nebel, 1923; and Wanless, 1929, 
1957) located within and near this area 
also contain sections on ground water. 

Leverett (1899) discussed the glacial 
geology and the occurrence of ground wa- 
ter in this area, Foster (1956) described 
the ground-water geology of nearby Lee and 
Whiteside Counties, and Horberg (1950, 
1956) studied the bedrock topography and 
glacial deposits of the area. 

This report is based on data from the 
files of the Illinois State Geological Survey 



STEPHENSON ~T' 

ROCK RIVER 




FIG. 1 — Rock Island, Monmouth, Galesburg, 
and Kewanee area of Illinois. The heavy 
outline delineates the area studied. Physi- 
ographic divisions are shown. The dashed 
line is the drainage divide between the 
Mississippi and Illinois Rivers. 

and on new information collected during 
the investigation. Data include drillers logs, 
sample description logs, a few outcrop de- 
scriptions, and geophysical logs. Locations 
are given by county, section, township, and 
range. 



A^cVnowledgments 

We are pleased to acknowledge special 
assistance given by the members of the 
Geological Survey staff. Kemal Piskin pre- 
pared maps on drift thickness and drift 
aquifers that are the basis for those used in 
this report. John W. Vukovich prepared the 
cross section. 

Appreciation also is due to the water 
well drillers who have supplied information 
and to the late W. J. Downer, Chief, Bureau 
of Public Water Supplies, Illinois Depart- 
ment of Public Health, for water pumpage 
data. 



GEOGRAPHY 



Physiography and Drainage 

The Rock Island, Monmouth, Galesburg, 
and Kewanee area hes within two adja- 
cent physiographic provinces of western 
IlUnois (fig. 1), the Galesburg Plain and 
the Green River Lowland (Leighton, Ek- 
blaw, and Horberg, 1948, fig. 1). 

The Galesburg Plain, which includes 
most of the study area, is underlain by 
wind-blown silt (loess) and glacial pebbly 
clay (till). The land surface is level to un- 
dulatory and has low, glacially built ridges 
(end moraines). This subdued topography 
prevails except locally along minor streams 
where the relief is 50 to 75 feet and along 
the Mississippi and Rock Rivers where 100 
to 150 feet of relief has been extensively 
developed. Much of the land surface con- 
figuration is controlled by the shape of the 
underlying bedrock surface. An end mo- 
raine separates the Galesburg Plain from 
the Green River Lowland. 

The Green River Lowland includes all 
of northeastern Henry County and is a low 
plain with prominent sand ridges and dunes 
and poorly developed surface drainage. The 
lowland coincides in large part with the 
broad buried valley of the Ancient Missis- 
sippi River, which formerly flowed south- 
eastward from north of Cordova in Rock 
Island County to the vicinity of Hennepin 
in Putnam County, then south along what 
is now the lUinois River Valley. 

The highest elevations within the area 
are found between Galesburg and Kewanee 
where elevations of 800 to 850 feet above 
sea level are common. The lowest eleva- 
tion is about 530 feet above sea level and 
occurs where the Spoon River crosses the 
southern boundary of Knox County. Near 
the Mississippi River in the northwest cor- 
ner of the area, the land surface elevation 
is slightly less than 560 feet above sea 
level. 

The Mississippi and Illinois Rivers are 
the major drainage lines of western Illinois. 
The divide separating their drainage basins 
lies partly within the area of study (fig. 1 ) . 



It runs generally northeast from southwest- 
ern Warren County, passing near Gales- 
burg, Galva, and Kewanee. The drainage 
patterns on either side of this divide differ. 
Rivers and streams on the northwest side 
generally follow subparallel courses from 
east to west, except in northern Rock Island 
and Henry Counties where they flow north- 
ward into the Green, Rock, and Mississippi 
Rivers. On the southeast side of the divide, 
streams and rivers are much more irregular 
in course and generally flow toward the 
south and east. 

The Mississippi River Valley is only 1 Vi 
to 2 miles wide along the northern bound- 
ary of the study area, but to the west 
where the river follows a preglacial bed- 
rock valley, the river valley is 7 to 8 miles 
wide. 

Climate 

The climate of the area is continental, 
with warm summers and cold winters (State 
of Illinois, 1958). Precipitation varies and 
a wide range of temperatures occurs dur- 
ing the year. 

The average annual precipitation is 34 to 
35 inches per year. The lowest average pre- 
cipitation generally occurs in February and 
is about 1 inch, according to records at 
Moline. June and September have the larg- 
est average monthly amounts, about 4.5 
and 4.1 inches, respectively. Once in 5 
years the annual precipitation reaches a 
low of about 28 inches; the highest annual 
precipitation is about 38 inches. 

January mean temperatures range from 
22° F in northern Rock Island County to 
28° F in the southern part of the area. 
Mean temperatures in July range from 74° 
to 78° F for the entire area. The average 
length of the growing season in most of the 
area is 170 to 180 days. 

Population 

In 1960, 300,324 people lived in the five- 
county area (U. S. Census Bur., 1963). 
The population in 1965 was estimated to 
be 308,400 (111. Tech. Advis. Comm. on 
Water Res., 1967, p. 23). Table 1 gives the 



10 



Table 1 — Population and Water Pumpage 





Population in I960" 






Water pumpage (1000 gpd) 


b 














Estimated 
















non- 








Calculated 




Municipal 


■■ Municipal" 


municipal* 








non- 




(ground 


(surface 


(ground 


Estimated 


County 


Municipal''' 


municipal =•= 


Total 


water) 


water) 


water) 


total 


Henry 


31,498 


17,819 


49,317 


2,340 


— 


890 


3,230 


Knox 


47,586 


13,694 


61,280 


7,985 


— 


685 


8,670 


Mercer 


8,373 


8,776 


17,149 


565 


— 


438 


1,003 


Rock Island 


122,990 


28,001 


150,991 


852 


16,556 


1,400 


18,808 


Warren 


13,415 


8,172 


21,587 


967 
12,709 


— 


409 


1,376 


Totals 


223,862 


76,462 


300,324 


16,556 


3,822 


33,087 



1 U. S. Bureau of the Census, 1963. 

^ Pumpage data provided by Bureau of Public Water Supplies, Illinois Department of Public Health. 

* In this chart, "municipal" refers to all incorporated communities and all unincorporated commvmities of 
over 1000 that have a public water supply. "Nonmunicipal" includes rural areas and all vmincor- 
porated communities of less than 1000, with or without public water supplies. 



total population of each county and the 
number of people in each county who are 
served by public water supplies derived 
from both surface and ground water and 
who live in communities of over 1,000 
population (table 2, fig. 2). In the five- 
county area, 223,862 people live in such 
communities, 111,300 of whom use surface 
water and 112,562 of whom use ground 
water. If it is assumed that people who live 
in rural areas and in nonmunicipal unin- 
corporated communities of less than 1,000 
also rely on ground water, a total of 
189,024 people use ground water. 

Of the total population, 175,239 people 
live in Monmouth, Galesburg, Kewanee, 
and Rock Island and its neighboring cities 
of Moline and East Moline. Eighty-three 
percent of the population of Rock Island 
County is classified as urban. 

Economy and ISlatural Resources 

Diverse elements are present in the econ- 
omy of this area (table 3). The value of 
agricultural products exceeds that of manu- 
factures in Henry, Mercer, and Warren 
Counties. Rock Island County has 76 per- 
cent of the total value of manufactures and 
Knox County 17 percent. Rock Island 
County also has 50 percent of the total re- 
tail trade and 61 percent of the total shop- 
ping goods sales. The Rock Island area is 
a center for the manufacture of farm ma- 



chinery and has the largest manufacturing 
arsenal in the United States. 

Beef cattle and hogs are the major 
sources of farm income (Ross and Case, 
1956). Forty percent of the crop and 
pasture land in 1955 was planted with corn, 
which is the principal cash grain crop. 

The mineral resources of the area include 
coal, stone, clay products, common gravel, 
common sand, and natural bonded molding 
sand, whose total production in 1965 had 
a value of nearly 1 4 million dollars (Busch, 
1967, p. 5-6). 

About 1.4 million tons of coal, with a 
value of over five million dollars, was pro- 
duced in 1965, nearly all of it from strip 
mines in southeastern Knox County. Small 
underground mines also are worked in Mer- 
cer and Henry Counties. The coals now be- 
ing mined are the Springfield (No. 5), the 
Herrin (No. 6), and the Rock Island (No. 
1 ) . More than five billion tons of strippable 
coal (coal 18 inches or more thick and with 
overburden not exceeding 150 feet) re- 
serves have been delineated with reason- 
able certainty in the area (Smith and Berg- 
gren, 1963, table 6). 

All counties in the area produce stone, 
Rock Island County being one of the larg- 
est producers in the state. The stone is pro- 
duced from quarries in the Silurian, Devo- 
nian, and Mississippian rocks and is used 
mainly for road building and agricultural 
limestone. 



11 




FIG. 2 — Principal geographic features of the Rock Island, Monmouth, Galesburg, and Kewanee area 

GEOLOGY 



Stratigraphy of the Bedrock 

The bedrock of the area ranges in age 
from Precambrian to Pennsylvanian (fig. 
3 ) , although the only rocks exposed at the 
surface are of Silurian age or younger (fig. 



4). The bedrock is covered by glacial de- 
posits in most of the area. However, out- 
crops and well records permit a reasonably 
reliable interpretation of the character and 
distribution of the bedrock formations. The 
cross section in figure 5 shows the se- 
quence and structure of the rocks in the 
area. 



12 



Table 2 — Municipal* Water Supplies 



Name 



Populationt 



Date*^ 
begun 



Apparent source of water 



Pumpagel- 
(1000 gpd) 



HENRY COUNTY 



Alpha 



637 



1900 



Annawan 


701 


1947 


Atkinson 


944 


1915 


Bishop Hill 


164 


— 


Cambridge 


1,665 


1896 


Colona 


491 




Galva 


3,060 


1894 


Geneseo 


5,169 


before 
1887 


Kewanee 


16,324 


1883 or 
1884 



Devonian-Silurian (Hunton), 
Galena-Platteville, 
Glenwood-St. Peter (Ancell) 
Devonian-Silurian (Hunton) 

Devonian-Silurian ( Hunton ) 
Devonian-Silurian ( Hunton ) , 
Galena-Platteville, 
Glenwood-St. Peter (Ancell) 
Devonian-Silurian (Hunton) 

Devonian-Silurian (Hunton), 
Galena-Platteville, 
Glenwood-St. Peter (Ancell) 
Devonian-Silurian (Hunton) 
Devonian-Silurian (Hunton), 
Galena-Platteville, 
Glenwood-St. Peter (Ancell) 
Drift 

Galena-Platteville, 
Glenwood-St. Peter (Ancell), 
Prairie du Chien, 
Eminence-Potosi, 
Ironton-Galesville 



45 



12 

65 
50 



8 

170 



50 

425 



410 
1000 



Orion 
WoodhuU 



1,269 

779 



1927 Devonian-Silurian (Hunton) 

1902 Devonian-Silurian (Hunton), 

Galena-Platteville , 

Glenwood-St. Peter (Ancell) 



75 
30 







KNOX COUNTY 


Abingdon 


3,469 


1902 


Glenwood-St. Peter (Ancell) 
Prairie du Chien, 
Eminence-Potosi, Franconia, 
Ironton-Galesville 


Altona 


505 


1952 


Devonian-Silurian ( Hunton ) 


Galesburg 


37,243 


1890 


Drift 


Knoxville 


2,560 


1896 


Galena-Platteville, 
Glenwood-St. Peter (Ancell) 
Prairie du Chien, 
Eminence-Potosi, 
Ironton-Galesville 


Maquon 


386 


1953 


Devonian-Silurian (Hunton) 


Oneida 


672 


1945 


Devonian-Silurian (Hunton) 



Rio 

St. Augustine 
Victoria 

Wataga 
Williamsfield 
Yates City 



177 
201 
453 

570 
548 
802 



1958 

1950 

1955 
1939 
1940 



Devonian-Silurian (Hunton) 
Keokuk-Burlington 
Devonian-Silurian (Hunton) 



Devonian-Silurian 
Devonian-Silurian 
Drift 



(Hunton) 
(Hunton) 



2016 



25 
5500 

210 



13 
30 

9 

10 

22 

25 
60 
65 



{Continued on next page) 



Table 2 — Continued 



13 



Name 



Populationt 



Date* = 
begun 



Apparent source of water 



Pumpage-i- 
(1000 gpd) 



Aledo 

Joy 

Keithsburg 

Matherville 
New Boston 
New Windsor 

North Henderson 
Seaton 
Sherrard 
Viola 



3,080 

503 
963 

612 

726 
658 

210 

235 
574 
812 



MERCER COUNTY 

1894 Devonian-Silurian (Hunton), 

Glenwood-St. Peter (Ancell) 

1923 Devonian-Silurian (Hunton) 
1893 Drift 

1952 Devonian-Silurian (Hunton) 

— Drift 

1924 Devonian-Silurian (Hunton) 

1957 Devonian-Silurian (Hunton) 

1912 Devonian-Silurian (Hunton) 

1951 Devonian-Silurian (Hunton) 

1915 Galena-Platteville, 

Glenwood-St. Peter (Ancell) 



280 

40 
40 

31 
22 
30 

20 
18 
30 

54 



Andalusia 
Carbon Cliff 

Coal Valley 

East Moline 
Hampton 
Milan 
Moline 
Port Byron 

Reynolds 
Rock Island 
Silvis 



560 
1268 

435 

16,732 
742 

3,065 
42,705 

1,153 

494 
51,863 

3,973 



ROCK ISLAND COUNTY 

1955 Devonian-Silurian (Hunton) 

1951 Galena-Platteville, 

Glenwood-St. Peter (Ancell) 
1902 Devonian-Silurian (Hunton) 

1895 Surface 

— Surface (from East Moline) 
1894 Devonian-Silurian (Hunton) 

— Surface 

1934 Devonian-Silurian (Hunton) 

1953 Devonian-Silurian (Hunton) 

— Surface 

1910 Galena-Platteville, 

Glenwood-St. Peter (Ancell), 
Prairie du Chien, 
Eminence-Potosi 



45 
34 

40 

3480 

38 

330 

5850 
58 

32 

7226 

275 



WARREN COUNTY 



Alexis 


878 


1895 


Kirkwood 


771 


1894 


Little York 


329 


1915 


Monmouth 


10,372 


1886 


Roseville 


1,065 


1895 



Devonian-Silurian (Hunton), 
Galena-Platteville, 
Glenwood-St. Peter (Ancell) 
Keokuk-Burlington, 
Devonian-Silurian ( Hunton ) , 
Galena-Platteville , 
Glenwood-St. Peter (Ancell) 
Devonian-Silurian (Hunton) 
Glenwood-St. Peter (Ancell), 
Prairie du Chien, 
EmJnence-Potosi, 
Ironton-Galesville 
Drift 



45 
37 



25 
800 



60 



* As defined in table 1. 
t U. S. Bureau of the Census, 1963. 
'*From Hanson (1950, 1958, 1961). Where no date is gi 

stalled subsequent to Hanson's publications. 
t Pumpage data provided by Bureau of Public Water Supplies, Illinois Department of Public Health. 



the water supply apparently Avas iu- 



The sequence of sedimentary rocks in 
this area is similar to that found in several 
other parts of Illinois for which reports have 
been published (Willman and Payne, 1942; 



Buschbach, 1964; Bell et al., 1964). These 
reports provide a basis for interpreting the 
sedimentary rocks and the geologic history 
of the area. 



14 



Table 3 — Economic Data ior the Rock Island, Monmouth, Galesburg, and Kewanee Area^ 





Total retail 

trade 

($1,000) 


Shopping 

goods sales 

($1,000) 


Value of 
manufactures 
($1,000) 


Agriculture 


County 


Number of 
farms 


Total value of 
products sold 
($1,000) 


Henry 
Knox 
Mercer 
Rock Island 
Warren 


73,358 
92,421 

21,573 

226,140 

31,763 


8,145 

15,102 

801 

42,378 
2,415 


20,384 
63,679 

t 
280,526 

4,170 


2,702 
2,034 
1,539 
1,360 
1,413 


58,851 
30,190 

25,317 
16,645 
33,168 


Totals 


445,255 


68,841 


368,759 


9,048 


164,171 



* Rand McNally and Co., 1966. Data are for 1963. 
t Separate figures are not available. 



The detailed information available from 
a deep stratigraphic test well near Rock 
Island (Buschbach, 1965) was used in the 
following lithologic descriptions. Busch- 
bach's sample description of the E. A. 
South No. 1 well is given in the Appendix to 
this report. Those aspects of the available 
geologic information most relevant to 
ground water are emphasized. 



PRECAMBRIAN ROCKS 

Only one test hole in this area has pene- 
trated Precambrian granodiorite and that, 
described by Buschbach (1965), had a 
total depth of 3,855 feet. Crystalline rocks 
such as the granodiorite found in the test 
probably underlie all of western Illinois 
(Bradbury and Atherton, 1965) and are 
well below the depths of potable ground 
water. 



CAMBRIAN SYSTEM 

Mt. Simon Sandstone 

The Mt. Simon Sandstone has been pene- 
trated by at least two water wells and two 
oil test wells within the area of study. In the 
northern part of the area, several wells for 
which no detailed information is available 
penetrate part of the Eau Claire Formation 
and may extend into the upper part of the 
Mt. Simon. It is assumed that the Mt. Simon 
underlies the entire region, although in a 
few places elsewhere in western Illinois it 
is locally absent, and hills of Precambrian 



rocks are overlain directly by the Eau 
Claire Formation (Bell et al., 1964). 

The Mt. Simon consists of fine- to 
coarse-grained sandstone and some varie- 
gated shale. The sandstone is typically poor- 
ly sorted, friable, and nondolomitic. The 
top is commonly picked on the basis of the 
first occurrence of scattered, very coarse 
sand grains in conjunction with the presence 
of "sooty" grains and the absence of dolo- 
mite and glauconite. 

The character of the Mt. Simon Sand- 
stone and other deep formations is shown 
by the description of the core from the deep 
stratigraphic test well (Appendix, log 1). 
It is 887 feet thick just west of the study 
area in sec. 19, T. 13 N., R. 4 W., Mercer 
County, and is 1,255 feet thick near the 
north-central part of the area in sec. 30, T. 
16 N., R. 1 E., Henry County. It is thought 
to thicken regularly eastward (Bell et al., 
1964, fig. 7). 

Eau Claire Formation 

At least 1 3 wells or test holes, including 
the four holes that enter the Mt. Simon, are 
known or assumed to penetrate the Eau 
Claire Formation. The Eau Claire con- 
sists of sandstone, siltstone, shale, and some 
dolomite. The sandstone is silty, dolomitic, 
and glauconitic, and it is the predominant 
rock type of the Eau Claire in this area. 
Shale is most abundant near the middle of 
the formation, and the dolomite occurs near 
the top. 

The thickness of the Eau Claire in this 
area is estimated to range from 225 to 300 



15 



feet. In the log of the deep stratigraphic 
test (Appendix, log 1 ) the Eau Claire For- 
mation is 294 feet thick. Regional studies 
suggest that it is thickest in the southeast 
(Belletal., 1964, fig. 7). 

Ir ontori'Galesville Sandstone 

The Ironton and Gales ville Sandstones, 
differentiated in outcrop and in the sub- 
surface in northeastern Illinois (Buschbach, 
1964), are difficult to distinguish in this 
area. Consequently, they are treated as one 
unit and called the Ironton-Galesville Sand- 
stone in this report. 

The Ironton-Galesville is penetrated par- 
tially or completely by at least 24 wells or 
test holes within the area of study. Eleven 
of these partially penetrate the unit, nine 
penetrate fully and extend short distances 
into the Eau Claire, and four extend into 
the Mt. Simon. 

The Ironton - Galesville is composed 
chiefly of white, fine- to medium-grained, 
slightly dolomitic sandstone (Emrich, 
1966). Near the top, the sandstone is me- 
dium grained but contains some coarse 
grains, is partly glauconitic, and is common- 
ly dolomitic. Most of the lower part of the 
Ironton-Galesville is fine-grained sandstone 
that is friable and slightly dolomitic. 

The Ironton-Galesville ranges in thick- 
ness from almost 200 feet in eastern Knox 
County and southeastern Henry County, to 
an estimated 100 feet in southwestern War- 
ren County, and to about 125 feet in north- 
ern Rock Island and Henry Counties (fig. 
6). Less than 50 miles south of the area, 
the sandstone wedges out. In the deep stra- 
tigraphic test well (Appendix, log 1), the 
Ironton-Galesville is represented by 23 feet 
of dolomite and 106 feet of sandstone. 

In figure 7, the depth to and elevation 
(below sea level) of the top of the Ironton- 
Galesville are given for most of the deep 
wells in the area. Data were considered in- 
sufficient for the construction of more than 
a very generalized structure map of the top 
of the formation. The most accurate esti- 
mates of depths and elevations for the 
Ironton-Galesville will be for locations close 
to datum points in figure 7. Between points, 



elevations can be interpolated and estimates 
of depth obtained by subtracting algebraic- 
ally the sandstone elevation from the land 
surface elevation. 

Alternatively, the depth to the Ironton- 
Galesville can be estimated by using thick- 
nesses taken from figure 8 (thickness of the 
interval between Ironton-Galesville and 
Glenwood-St. Peter) and elevations from 
the Glenwood-St. Peter structure map. 



Franconia Formation 

The Franconia Formation is partially 
penetrated by three wells and fully pene- 
trated by the 24 wells noted above that ex- 
tend to deeper units. The Franconia is 
fine-grained, glauconitic sandstone inter- 
bedded with sandy, glauconitic dolomite 
and silty, glauconitic shale. 

The formation thickens to the south and 
southwest, from 130 to 150 feet near the 
boundary between Henry and Bureau Coun- 
ties and 120 feet in central Rock Island 
County to 200 feet in Mercer County and 
250 feet in central Warren County. 



Potosi Dolomite and Eminence 
Formation 

The Potosi Dolomite and the Eminence 
Formation were formerly called the Trem- 
pealeau Dolomite and the Jordan Sand- 
stone. Now in Illinois the name Jordan 
Sandstone is recognized in only the north- 
western part of the state. 

The Potosi Dolomite and the Eminence 
Formation are partially penetrated by at 
least 10 wells within the study area in addi- 
tion to the 27 wells that extend to deeper 
units. The Potosi Dolomite is a fine-grained, 
light grayish brown, slightly glauconitic 
dolomite that contains drusy quartz. The 
overlying Eminence Formation consists of 
light brown to light gray, fine- to medium- 
grained sandy dolomite containing oolitic 
chert. Beds of dolomitic sandstone also are 
distributed throughout this unit. A well de- 
veloped sandstone, the Momence Sand- 
stone Member, is present at the base. To 
the north of the study area the Eminence 



16 



SYSTbM 



GROUP 
OR 

FORMATION 



CRAPHIC 
LOG 



miCK- 
NESS 
(FT) 



DHSCRIPTION 



DRILLING 

& CASING 

CONDITIONS 



WAThR-YILLDING PROPERTIES 



^ M < 



PLEIS- 
TOCENE 



0-230 



"■9" 



Unconsolidated 
glacial de- 
posits loess 
and alluvium 



Wells usually 
need careful 
development 
and screens 



Variable; large yields from 
thicker sand & gravel de- 
posits in bedrock valleys 



0-400 



Mainly shale 
with sand- 
stone, lime- 
stone, and 
coal 



Casing usually 
required 



Generally unfavorable as 
aquifer; domestic and farm 
supplies obtained from 
thin limestone and sand 
stone beds locally 



Salem- 



^^^ 



0-30 



Sh, ss, and Is 



ta tt 



Casing usually 
required 



Not water yielding at most 
places 



Keokuk Ls 

Burlington 
Ls 



rTT A l 



ta 



±11 



0-170 



Limestone 



UEJ 






Generally creviced, water 
yielding; wells penetrate Is 
from 30 to more than 150 ft; 
dependable aquifer for farm 
supplies in much of area 






Chouteau 



da 



nn 



New AlbanyfE 
Group 



nzn 



0-275 



Shale 



Casing re- 
quired 



Not water yielding at most 
places; limestones within 
shale are source of small 
farm supplies locally 



UPPER 



^ 



MIDDLE 



^ 



Hunton 
Megagroup 



77 777: 



S 



-Tin 



77T7 



ALEXAN- 
DRIAN 



iSi 



IZZi 



wn 



20- 

140 



Limestone 



Dolomite J 
cherty 
at base 



Devonian limestone locally 
water yielding from crev- 
ices; Silurian dolomite more 
dependable aquifer for farm 
supplies in most areas; sat 
isfactory wells may require 
penetration from 25-150 ft 
into Silurian; dolomite usu 
ally "tighter" in lower half 






Maquoketa 
Group 



^ 



200- 
215 



Green to blue 
and brown 
shale with 
limestone 
and dolomite 



Shale requires 
casing 



Generally not water yielding 



T7T77 



r xi . 



"^ o 
c t< 



O i^ 



77777 



X-I 



rzr 



IZI 



300- 
320 



S 



Dolomite with 
shaly zone 
near middle; 
limestone in 
lower part 



Crevicing not 
common 



Not important as aquifer; 
crevices yield some water 



LZJI 



rn 



i-j- 



Ancell Gr 

(Glenwood-f^ 

St. Peter 

Ss) 



70- 
250 



Sandstone; 
green shale; 
cherty shale 
at base 



Shale may re- 
quire casing; 
sand may 
cave 



Dependable source of 
ground water 



FIG. 3 — Geologic formations of the Rock Island, Monmouth, 



17 



SYSTEM 



SERIES 



GROUP 

OR 

FORMATION 



GRAPHIC 
LOG 






THICK- 
NESS 
(FT) 



DESCRIPTION 



DRILLING 

5 CASING 

CONDITIONS 



WATER-YIELDING PROPERTIES 



i 



O 



Shak- 
ppee 



S^ 



80- 

275 



iS 



Dolomite with 
some shale 
and sand- 
stone 



New 
Rich- 
mond Ss 



JII.\ 



40- 
90 



Sandstone with 
some dolo- 
mite 



Oneota 
Dol 



S 



LX2 



E 



200- 
300 



Dolomite, 
cherty 



^ 



Eminence 
Fm 



mn 



50- 
120 



e 



Dolomitic sand- 
stone and 
sandy dolo- 
mite 



Casing not 
required; 
crevices 
encountered 
locally 



Some water from sandstones 
and creviced dolomite; not 
developed for large supplies 



Potosi 
Dol 



e 



Tn. 



150- 
200 



Dolomite with 
drusy quartz 



rn 



JjJZ 



Franconia 

Fm 



^ 



120- 
200 



Green sand- 
stone, shale, 
and dolomite 



Ironton- 

Galesville 

Ss 



'.i-l: 



100- 
200 



Sandstone, 
partly 
dolomitic 



May cave 



Widespread and important 
aquifer for large supplies 



Eau Claire 
Fm 



225- 
300 



Bandstone and 
shale with 
some dolo- 
mite 



Weak shales 
may require 
casing 



Some water from sandstone 



Mt. Simon 
Ss 



800- 
1300 



Sandstone, 
beds of shale 
and siltstone 



Casing not 
required 



Water yielding 



'W^v'W' 



PRECAMBRIAN 




Igneous rock 



Not water yielding 



Galesburg, and Kewanee area and their water-yielding properties. 



^/^y/ //y ///////// / ^ /^\ 




V ' ' * ' 



PENNSYLVANIAN SYSTEM 

Shale, sandstone, limestone, coal 

MISSISSIPPIAN SYSTEM 
Mainly limestone 

MISSISSIPPIAN AND DEVONIAN SYSTEMS 
New Albany Group - shole 

DEVONIAN SYSTEM 
Limestone 

SILURIAN SYSTEM 

Niagaron Series - dolomite 
Alexandrian Series -dolomite 



SUBSURFACE BOUNDARIES 

, Northern limit, Devonian age limestone 

*-• '^' — •* Northern limit, New Albany Group shale 
^•••w-'"-- Northern limit, Mississippian age limestone 

. Southwestern limit, Niagaron Series 

•'"•..... Southwestern limit, Alexandrian Series 



a' 

"^ Line of cross section, figure 5 



FIG. 4 — Bedrock geologic map with selected subsurface geologic boundaries. 



19 



thins slightly and becomes increasingly 
sandy, grading into the Jordan Sandstone. 
A description of the Eminence and Poto- 
si Formations in this area is included in the 
record of the deep stratigraphic test in 
Henry County (Appendix, log 1). In that 
well the Potosi is 166 feet thick and the 
Eminence 61 feet thick. In southeastern 
Henry County, sec. 4, T. 14 N., R. 5 E., 
the Potosi is 190 feet thick and the Emi- 
nence 1 1 5 feet thick. 

ORDO VICIAN SYSTEM 

Prairie du Chien Group 

The Prairie du Chien Group in the study 
area is partially penetrated by at least 20 
wells and is completely penetrated by the 
37 wells and test holes that reach deeper 
units. The formations composing this group 
consist of partly cherty, partly sandy dolo- 
mite, with some sandstone interbedded. The 
group underlies all of this area, and is di- 
vided into three formations, the Oneota 
Dolomite, the New Richmond Sandstone, 
and the Shakopee Dolomite, in ascending 
order. East and south of the area of study, 
an additional formation, the Gunter Sand- 
stone, occurs below the Oneota. The Shako- 
pee Dolomite was partly eroded before dep- 
osition of the overlying Ancell Group be- 
gan. The thickness of the Prairie du Chien, 
therefore, is irregular. 

The Oneota Dolomite is generally light 
gray, medium grained and cherty. Thick- 
nesses of about 225 to 250 feet have been 
reported in Rock Island County. In Knox 
County it is 275 to 300 feet thick. 

The New Richmond Sandstone consists 
of dolomitic, fine- to medium-grained sand- 
stone and sandy, fine-grained dolomite. The 
formation is 45 to 50 feet thick in the Rock 
Island vicinity, thickens from 75 to 90 
feet in Henry and Knox Counties, and 
reaches 175 feet in north-central Illinois. 
In Warren and McDonough Counties it ap- 
pears to thin markedly but perhaps irregu- 
larly. It terminates a short distance to the 
south of the study area. 

The Shakopee Dolomite is a very fine- 
grained, gray or reddish gray dolomite con- 



taining some chert. It has been thinned by 
pre-St. Peter erosion and ranges in thickness 
from 83 to 275 feet. Most of the thinning 
is in the northeastern part of the area. 

The sample study of the City of Kewanee 
No. 4 well (Appendix, log 2) shows the 
characteristics of the Prairie du Chien 
Group. 

Ancell Group 

The Ancell Group, which in the study 
area consists of the Glenwood Formation 
and the St. Peter Sandstone, underlies the 
entire area, where it is penetrated by at 
least 87 wells and test holes. Thirty of these 
partially penetrate the Ancell, 18 penetrate 
the full thickness but extend only a few 
feet into the Shakopee, and 39 extend to the 
New Richmond or deeper units. 

The Ancell Group consists of four rock 
units in much of this area. These units are 
most easily differentiated in south-central 
Rock Island County where they have been 
penetrated by several structure tests in 
which geophysical logs were run. 

The basal unit of the Ancell Group is 
characterized by a predominantly green 
shale containing chert and some sandstone. 
This is the Kress Member of the St. Peter 
Sandstone. The Kress is usually thin (2 to 
10 feet) but in some places reaches thick- 
nesses of 30 to 40 feet. It is irregular in dis- 
tribution and is thought to be the initial de- 
posit of the Ancell Group. 

A white, fine-grained sandstone, the Ton- 
ti Member of the St. Peter Sandstone, 
overlies the Kress Member. It is present in 
the entire study area and is irregular in 
thickness, ranging from 60 to about 100 
feet. 

Above the white Tonti Sandstone is a 
complex unit that is largely of green, sandy 
shale and is called the Kingdom Member of 
the St. Peter Sandstone. It underlies all of 
the area of study except southeastern Knox 
County, being thickest in south-central 
Rock Island County where it reaches a 
maximum of almost 25 feet; it thins to the 
south and east. In the areas of thinning it 
may be discontinuous. In well cuttings, if 
the green shale is absent it may be difficult 



20 




! 



21 




. — /50 Thickness, interval 
50 feet 



SCALE 

10 20 



• Datunn point. May 
represent nnore than 
one well. Numbers 
give logged thickness 
i°'^'^^^ in feet. 



FIG. 6 — Thickness of the Ironton-Galesville Sandstone. (Modified from Emrich, 1966.) 



22 




Well 
2262— Depth of sandstone (ft) 

Elevation of sandstone (ft) 



SCALE 

10 20 



30 MILES 



FIG. 7 — Depth and elevation of the top of the Ironton-Galesville Sandstone. 



to distinguish the Tonti Sandstone Member 
from the uppermost sand unit, the Starved 
Rock Member of the St. Peter, and from 
the Glenwood Formation. 

The upper sand unit is a white, fine- to 
medium-grained, friable sandstone that in 



the Rock Island area contains at least two 
beds of green shale that may be of limited 
areal extent. This sandstone is 60 to 70 feet 
thick in the southern part of the area and 
thins northward. It is absent north of a 
boundary that approximates the position of 



23 




— ^-^_ leoo 



BOO 



1164 



969 •949 



986 



1045 



1039 



*->.4 ^^lOOO 

1040 



1058 



H47 
165 




1254 



- ^ --t „n^ [ 



^^iioo 



1200 



1281 



,300 



900 Thickness, interval 
100 feet 



1230 



Well numbers give 
logged thickness in 
feet 



SCALES 



20 



30 MILES 



FIG. 8— Thickness oi the interval between the top of the Glenwood-St. Peter Sandstone (Ancell 
Group) and the top oi the Ironton-Galesville Sandstone. 



the Mississippi River at the Tri-Cities. It 
may extend a short distance farther north in 
eastern Rock Island County. 

The four units of the Ancell Group are 
differentiated in the description of core 
from the deep stratigraphic test well (Ap- 



pendix, log 1 ) . The thickness of the Ancell 
Group is irregular and no attempt was made 
to draw thickness contours for it. Instead, 
reported thicknesses for the group are 
shown in figure 9. Since the Ancell Group 
is the deepest sandstone aquifer for which 



24 



a moderate amount of data is available, a 
structure map of its top was made (fig. 10) . 

Platteville and Galena Groups 

Within the area of study, 23 wells and 
test holes of record terminate in the Platte- 



ville and Galena Groups (Ottawa Mega- 
group). The Platteville Group consists of 
gray or brown, very fine-grained dolomite 
and limestone. The overlying Galena Group 
is chiefly medium-grained, buff-colored 
dolomite with reddish brown shale partings 



t'^ 



80 

•120 

97 



• 176 



^32+ 



13 + 



152 



14+ 



,10+ 



.151 




• 55 



• 134 



"1 



173+ 206 I ••,20 100 

'^i 1*20 '^^•88,98 
148.^ ^•85+ 
102 97 

112 



.198+ 



127 + 



44 + 



134 



134 

• 34+ 

44+ •101 + 



20 + 



.141+ I 
156 I6^^®» ,,^. 

• •'^^^ 185 'Tl^r;2oo 

140 ^70+ 245+ " 
143 
• 145 
.200 
^ •t58 



• 100+ 



120 + 



f 



;35+ 




225+ 



155+ •193 



152 



270 

• 210 + 



Datum point. May represent more 
than one well. Numbers give logged 
thickness in feet. 



SCALE 
10 ao 



30 MILES 



FIG. 9 — ^Thickness of the Glenwood-St. Peter Sandstone (Ancell Group). 



25 



at the base. The combined thickness of the 
two groups averages between 300 and 320 
feet in the area. 

Maquoketa Group 

The Maquoketa Group consists of two 
units of dolomitic and silty shales that are 
separated by a silty dolomite. The group 
averages between 200 and 215 feet thick 
in most of the area, but in southwestern 
Warren County it has been thinned by pre- 
Middle Devonian erosion. 

SILURIAN AND DEVONIAN 
SYSTEMS 

Hunton Megagroup 

The Hunton Megagroup includes carbo- 
nate rocks of Silurian and Devonian age. Its 
occurrence to the south in the subsurface 
was described by Whiting and Stevenson 
(1965). 

Hundreds of wells within the study area 
penetrate part or all of the Hunton. Of the 
records on file at the Illinois Geological 
Survey 185 were selected for this study. 
Records for wells to deeper horizons were 
also used. 

The Silurian strata are assigned to the 
Alexandrian and Niagaran Series. Alexan- 
drian rocks include yellowish gray, partly 
cherty dolomite overlying gray, argillaceous, 
dolomitic siltstone. The Niagaran rocks are 
light gray dolomite. The Silurian strata have 
been removed by erosion from southern 
Henderson County, extreme southwestern 
Warren County, and most of central and 
western McDonough County. The area 
from which Silurian rocks have been eroded 
is delineated by the line showing the south- 
western limit of the Alexandrian Series (fig. 
4); the Niagaran Series is present a few 
miles northeast of this line. Silurian rocks 
thicken in a northeasterly direction to a 
maximum of almost 400 feet. Irregularities 
in the thickness of the Silurian are attribut- 
able to pre-Middle Devonian and later ero- 
sion. 

Devonian strata underlie all of the report 
area except northeastern Rock Island Coun- 



ty where Silurian rocks are at the bedrock 
surface or lie directly below the Pennsylva- 
nian (fig. 4). The lower unit of the Devo- 
nian is the Wapsipinicon Formation, a 
brownish gray, sublithographic limestone. 
It is present in Rock Island, Mercer, Henry, 
and northern Warren and Knox Counties. 
In the rest of the area, it is generally 20 to 
40 feet thick. The overlying unit, the Cedar 
Valley Formation, is gray to brown lime- 
stone and some dolomite that is very fine 
grained and fossiliferous. It underlies all of 
the area except northeastern Rock Island 
and Henry Counties. Its thickness ranges 
from 20 feet to over 100 feet. 

The characteristics of the Hunton Mega- 
group are given in the partial sample study 
log of the Village of North Henderson No. 
1 well (Appendix, log 3). 

The thickness of the Hunton Megagroup 
ranges from less than 100 feet in the south- 
western part of the area where the Devo- 
nian rocks predominate to approximately 
400 feet in the northeastern part of the area 
where the Silurian (especially the Niaga- 
ran) rocks predominate (fig. 11). North 
of the northern limit of the New Albany 
Group (Lower Mississippian-Upper Devo- 
nian) (fig. 4), the Hunton Megagroup has 
been beveled by pre-Pennsylvanian erosion. 

DEVONIAN AND MISSISSIPPIAN 
SYSTEMS 

Upper Devonian and Lower Mississip- 
pian shale (Collinson, 1961) of the New 
Albany Group underlies all of the area ex- 
cept a band that varies in width across the 
northern part where the shale has been re- 
moved by pre-Pennsylvanian erosion (fig. 
4). The northern boundary of the shale is 
shown in figure 4 but is probably much 
more complex than is indicated. Between 
the eroded northern edge of the shale and 
the northern limit of overlying Keokuk-Bur- 
lington Limestone (fig. 4), the shale has 
been beveled by erosion. The New Albany 
Shale that is of Mississippian age probably 
is present only in the southern part of the 
area of study. The New Albany has a maxi- 
mum thickness of about 275 feet near the 
northern limit of the Keokuk-Burlington; it 



26 




-202 ^®" penetrating Ancell Group, 
witti elevation 



Datum point with elevation 
projected from higher formation 



^QQ^ Contour and elevation in feet; 
^ interval lOOfeet; datum mean 
sea level 

Half-interval contour 



FIG. 10 — Elevation of the top of the Glenwood-St. Peter Sandstone of the Ancell Group. Estimated 
thicknesses were projected downward from the tops of the Maquoketa and Galena Groups to 
supplement elevations of the top of the Ancell Group. 



27 



thins toward the south (Workman and Gil- 
lette, 1956, figs. 3 and 6). Included in the 
New Albany are a thin gray shale at the 
base, a dark brownish black, silty, Tas- 
manites-hesLYing shale, and a greenish to 
bluish gray shale. 

Above the New Albany Group lies the 
Keokuk-Burlington Limestone of Valmey- 
eran age. Records for 33 wells that pene- 
trate all or part of the Keokuk-Burlington 
were selected for this study, all of them in 
Knox and Warren Counties. Several of the 
wells also penetrate the Hunton Megagroup. 

The character of the Keokuk-Burlington 
and of the underlying shale is shown by the 
sample study log of a well in Knox County 
(Appendix, log 4). 

Above the Keokuk-Burlington is the 
Warsaw Shale, which is predominantly 
shale but includes some limestone, and the 
Salem Limestone, which is generally light 
brown, fossiliferous, and dolomitic and in- 
cludes some sandstone and siltstone. The 
Warsaw and Salem are present in west-cen- 
tral Warren County and in McDonough and 
Fulton Counties (Harvey, 1964). They 
have been beveled by pre-Pennsylvanian 
erosion. 



PENNSYLVANIAN SYSTEM 

Rocks of Pennsylvanian age were de- 
posited on the uneven surface of the under- 
lying Mississippian and older rocks. Penn- 
sylvanian rocks underlie all of the study 
area (fig. 4), except where they have been 
removed by preglacial erosion. The rocks 
are primarily shale but include various 
amounts of sandstone, underclay, coal, and 
limestone (Appendix, log 5). The sand- 
stones sometimes are found in channels, 
where they are relatively thick. The lower 
Pennsylvanian sandstones are conglomeratic 
in some places, although more commonly 
they are fine grained and silty. 



Structure of the Bedrock 

The bedrock formations of the study 
area, in general, dip gently southeast toward 
the center of the Illinois Basin. At various 



times during the deposition of the bedrock 
units, earth movements of both local and 
regional extent disturbed the structural at- 
titude of the sedimentary rocks. 

For the purposes of this study, the most 
important horizon for structural mapping is 
the top of the Glenwood-St. Peter Sand- 
stone, the Ancell Group (fig. 10), which 
is also the base of the Platte ville Group. 
This horizon is the top of a major sandstone 
aquifer, whose structure is probably similar 
to that of deeper sandstone units, including 
the Ironton-Gales ville. Structure of the 
Glenwood-St. Peter top is also essentially 
parallel to the top of the Galena Group and, 
in most of the area, to the top of the Ma- 
quoketa Group. In the construction of the 
structure map (fig. 10), estimated thick- 
nesses were projected downward from the 
tops of the Maquoketa and the Galena to 
supplement elevations of the top of the An- 
cell Group. The structure map of the top of 
the Galena Group presented by Whiting and 
Stevenson (1965, fig. 7) was followed in 
part in the contouring of figure 10, especial- 
ly for the northwest-southeast "grain" of 
the structure. 

Relatively intensive folding of the sedi- 
mentary rocks is found between northern 
McDonough and Fulton Counties on the 
south and south-central Rock Island County 
and southwestern Henry County on the 
north (fig. 10). Small, randomly oriented 
structures are present to the southwest of 
this area of folding (Whiting and Stevenson, 
1965, fig. 7) and, to a lesser degree, to the 
northeast of it. In the folded area, essen- 
tially parallel anticlines and synclines pre- 
dominate. 

Three small anticlinal domes have been 
defined by drilling within and near the area 
of study. They are located in south-central 
Rock Island County (Buschbach, 1965), 
southwest Mercer County, and southeast 
Henderson County. Similar structures may 
well be present elsewhere in the vicinity. 
For example, in central and northern War- 
ren County, and also in eastern Mercer 
County and southwestern Henry County, 
the data suggest the possibiHty of closed 
contours. 



28 




389+ 






403 
«426 



:4I0 



409 



323385 • 

335 M I 

395 ♦ ' 
394 



435 435 



453« 



416 



507 




.100 — Thickness, interval 100 feet; 
Hunton below the New 
Albany Group 

->,.-— Northern limit of the New 
Albany Group 



Well, with logged thickness 
of the Hunton, in feet 



SCALE 



10 



20 
I — 



30 MILES 



FIG. 1 1-— Thickness oi the Silurian-Devonian limestone and dolomite oi the Hunton Megagroup. 
Devonian rocks predominate in the southwestern pari of the area and Silurian rocks in the 
northeastern part. North of the northern limit of the New Albany, the Hunton Megagroup has 
Iseen beveled by pre-Pennsylvanian erosion. 



29 



No major faulting has been recognized 
in the area, but several major intervals of 
structural activity can be inferred from the 
rocks of this area. A structural uplift that 
took place at the end of Ordovician Prairie 
du Chien time led to erosion of the Shako- 
pee Dolomite to thicknesses of less than 100 
feet in several places in the northeastern 
part of the area. 

A broad uplift called the Sangamon Arch 
(Whiting and Stevenson, 1965) probably 
began in late Silurian time and persisted un- 
til after Middle Devonian time. The ero- 
sion that followed the formation of Silurian 
rocks removed several hundred feet of 
strata before Devonian deposition. All Si- 
lurian strata have been removed from ex- 
treme southwestern Warren County, from 
the southern half of Henderson County, and 
from the area farther to the southwest where 
Middle Devonian rocks rest on the eroded 
surface of the Ordovician Maquoketa Group 
(fig. 4). In most of the study area, how- 
ever, partially eroded Silurian dolomite un- 
derlies Middle Devonian strata. 

At the end of Mississippian time, a major 
structural disturbance resulted in the for- 
mation of the LaSalle Anticline (Willman 
and Payne, 1942). In the study area, a 
sharp unconformity at the base of the Penn- 
sylvanian gives proof of the disturbance. 
The unconformity truncates the Silurian in 
northern Rock Island County and, toward 
the south into southern Warren County, 
progressively younger rocks, including the 
Middle Devonian, the Upper Devonian and 
Lower Mississippian rocks, and the Middle 
Mississippian rocks. 

Glacial Geology and Bedrock 

Topography 

Four major stages of glaciation of the 
Pleistocene Series (fig. 3) are represented 
by the unconsolidated deposits found above 
the bedrock within and near the area of 
study. The bedrock surface upon which the 
deposits were laid had a complex erosional 
history (Horberg, 1946, 1950). It is char- 
acterized by broad uplands that have been 
incised by deep valleys. Between epochs of 
glaciation, normal weathering and erosion 



took place. Outcrops are common along 
streams in areas where the drift is thin. 

The oldest glacier, the Nebraskan, prob- 
ably entered the western part of the state 
and covered much of the study area. De- 
posits of till, sand, and gravel attributed to 
this glacier are found a short distance to the 
southeast of the study area (Wanless, 1957, 
p. 128). Deposits in northwestern Warren 
County and southwestern Mercer County 
have been identified as Nebraskan (Hor- 
berg, 1956), but may be Kansan in part 
(Frye, Willman, and Black, 1965). 

A lobe of ice of Kansan age from a north- 
western source covered this area and de- 
posited at least 78 feet of till, sand, and silt 
(Horberg, 1956, Pleistocene section 6). 
The following description of an exposure 
south of Rock Island shows a sequence of 
materials that is thought to be characteris- 
tic of much of the area (adapted from Hor- 
berg, 1956, Pleistocene section 1). 

Thickness Depth 
(ft) (ft) 

PLEISTOCENE SERIES 
WISCONSINAN STAGE 

Peoria Loess, yellowish 

brown, noncalcareous . . 10 10 

ILLINOIAN STAGE 
Truncated Sangamonian 

weathering profile 
Till, yellowish brown, 

clayey, noncalcareous . . 2 12 

Till, as above, gravel at 

base 7 19 

Loveland (?) clay 1 20 

KANSAN STAGE 

Truncated Yarmouthian 

weathering profile 
Till, dark, sandy, hard, 

calcareous 12 32 

Till, dark, calcareous 13 45 

Till, dark gray, calcareous 14 59 

Sand, silty, calcareous ... 12 71 

Sand, gravelly, calcareous 5 76 

Till, sandy, calcareous ... 4 80 

Early Kansan 

Silt and sand 3 83 

Silt 2 85 

The Illinoian glacier covered most of 
lUinois, including the area of study. Illi- 
noian deposits (see section described 
above) are usually less than 50 feet thick 
and are generally fine textured. 



30 



The Buffalo Hart Moraine, which defines 
one of the three substages of the lUinoian 
Stage, lies (fig. 12) just west of London 
Mills in Fulton County and runs generally 
northeast past Maquon to a point just west 
of Williamsfield in Knox County, then 
northwest past Oneida, and from there 
north-northeast to a point in central Henry 
County where it passes below younger de- 
posits. 

Deposits of the Wisconsinan Stage con- 
sist of tills and associated ice-contact de- 
posits in northeastern Henry County. The 
Shelbyville Moraine, which marks the west- 
ern limit of Wisconsinan glaciation (fig. 
12), enters Henry County just north of 
Kewanee and goes west for several miles 
before turning northwest and running past 
Geneseo into extreme northeastern Rock 
Island County. Loess of Wisconsinan age 
covers the entire area and is more than 25 
feet thick in some places along the Mis- 
sissippi River. Wisconsinan outwash, sand 
dunes, and lake beds are found along the 
major drainage lines, including the Missis- 
sippi, Rock, and Green Rivers. 

The physical properties of the glacial 
drift materials, particularly as they relate to 
their potential for water supply, and the 
thickness of the drift are quite varied. In 
large areas, the drift is less than 50 feet 
thick, but in a few places it may be more 
than 200 feet thick (fig. 13). It consists 
largely of till, as shown in the following 
record from Warren County. 

Monmouth School District No. 222, sec. 26, 
T. 11 N., R. 2 W., Warren County, Illinois. 
Total depth 1273 feet. Elevation 745 feet. Illi- 
nois Geological Survey sample set 28812. Drilled 
by K. Schmeiser. Studied by G. H. Emrich, July 
1957. 





Thick- 






ness 


Depth 




(ft) 


(ft) 


ISTOCENE SERIES 






No samples 


20 


20 


Till, silty, brown to light 






brown, leached 


5 


25 


Till, very silty, yellowish 






gray to gray, leached . . . 


5 


30 


Till, silty, yellowish buff, 






oxidized, calcareous. 






slightly sandy 


20 


50 



Areas of thick drift are relatively small 
(fig. 13). At three places within the area 
of study the drift thickness is known to ex- 
ceed 200 feet (fig. 13). In two of these 
(extreme northwest Warren County and 
northeast Henry County) the drift is asso- 
ciated with buried portions of the Ancient 
Mississippi River Valley, and in the third 
(south-central Rock Island County) there 
is a broad ridge on the land surface and a 
valley on the bedrock surface. Some areas 
of thick drift appear to be barren of per- 
meable materials, as is illustrated by the 
following record from Henry County. 

Elizabeth Edwards well, sec. 11, T. 16 N., R. 
1 E., Henry County, Illinois. Total depth 357 
feet. Elevation 709 feet. Illinois Geological Sur- 
vey sample set 15148. Drilled by Larson and 
Swanson. Studied by M. V. Strantz, 1946. 



Thick- 
ness Depth 
(ft) (ft) 
PLEISTOCENE SERIES 

Soil, noncalcareous, brown . . 4 4 

Silt, slightly calcareous, dark 

yellowish orange 26 30 

Till, calcareous, moderate yel- 
lowish brown 17 47 

Till, calcareous, dark yellow- 
ish brown 8 55 

Till, calcareous, moderate yel- 
lowish brown 10 65 

Till, calcareous, dark yellow- 
ish brown 23 88 

Till, calcareous, dark yellow- 
ish brown to gray 12 100 

Till, calcareous, grayish brown 50 150 

Till, calcareous, dark yellowish 

brown 7 157 



The deposits that occur at shallow depths 
along major glacial drainage lines common- 
ly consist of interbedded coarse- and fine- 
textured materials. These deposits, although 
of varied texture, are generally very perme- 
able and areally extensive. The following 
record shows the nature of the materials. 



Henry Martens No. 6 well, sec. 29, T. 18 N., 
R. 4 E., Henry County, Illinois. Total depth 42 
feet. Elevation 612 feet. Illinois Geological Sur- 
vey sample set 51536. Drilled by Gibbs Well 
Drilling Company. Drillers log, April 1965. 



31 




Major bedrock valley \,)^^^ Western limit of Wis- 



cut 200 to 300 feet 
below bedrock upland 

Bedrock valley cut 
100 to 200 feet below 
bedrock upland 

Bedrock valley cut 
less than 100 feet 
below bedrock upland 



consinan glaciation 

<<iLaA^ Front of Buffalo Hart 
(lllinoian) Moraine 



SCALE 
10 20 



30 MILES 



FIG. 12 — Bedrock valleys (after Horberg. 1950) and major drift boundaries. 



32 



Thick- 
ness Depth 

(/O (/O 
PLEISTOCENE SERIES 

Black sandy topsoil 1 1 

Fine sand 5 6 

Yellow clay 5 11 

Fine brown sand 7 18 

Coarse sand and gravel 4 22 

Fine sand 6 28 

Coarse sand and gravel 13 41 

Blue clay 1 42 

Much of the area is covered by a wind- 
blown silt called loess. In parts of the pres- 
ent uplands, especially near the Mississippi 
River, the drift is mainly loess. Pebbly clay 
till generally makes up the bulk of the gla- 
cial drift below the loess. Within the till, 
layers and lenses of sand and gravel may 
occur. A typical log showing the loess, till, 
and interbedded sand and gravel at Gales- 
burg is given below. 



City of Galesburg No. 3 well, sec. 2, T. 11 N., 
R. 1 E., Knox County, Illinois. Total depth 2473 
feet. Elevation 785 feet. Illinois Geological Sur- 
vey sample set 10725. Drilled by Thorpe Well 
Company. Studied by M. P. Meyer, 1943-1944. 



Thick- 
ness Depth 
ift) (ft) 
PLEISTOCENE SERIES 

Soil, black; silt, noncalcareous, 

yellowish gray 5 5 

Silt, slightly calcareous, yellow 5 10 

Silt, noncalcareous, slightly 

sandy, brown 5 15 

Till, noncalcareous, brownish 

gray to green, pebbly, silty. 10 25 

Gravel, coarse; sand, yellow, 
medium; silt, calcareous, 
gray 10 35 

Till, calcareous, sandy, gravel- 
ly, dark gray 40 75 

Sand, brown, coarse; gravel, 

fine to coarse 7 82 

Sand and gravel, which may have been 
deposited during more than one glacial 
stage, occur extensively in parts of northern 
Rock Island and Henry Counties. These 
materials were left by glacial meltwaters 
that carried and deposited rock debris down 
major valleys (fig. 12) . They are more com- 



mon in thick drift than in thin. The thick- 
ness and composition of the layers of sand 
and gravel can vary significantly within 
short distances; their presence cannot al- 
ways be predicted in advance of test drilling. 
In general, the areas where the drift 
thickness is more than 50 feet (fig. 13) are 
along bedrock valleys (fig. 12). Glacial 
deposits have completely filled some valleys 
and partially filled others. Sand and gravel 
deposits are numerous in the buried val- 
leys. 



GROUND WATER 

Water Pumpage 

The estimated total pumpage (table 1) 
for ground water and surface water in the 
region is 33,087,000 gallons per day (gpd) . 
Of this total, 16,556,000 gpd is surface 
water and 16,531,000 is ground water. The 
surface water pumpage, which constitutes 
about 50 percent of the total pumpage, is 
used to meet the needs of the 112,000 
population of Rock Island, Moline, and 
East Moline. This water is used for indus- 
trial as well as domestic and municipal 
purposes. 

County water pumpage varies with popu- 
lation and with the amount of industry lo- 
cated in the county. In total pumpage, Rock 
Island County ranks first, Knox is second, 
Henry third, Warren fourth, and Mercer 
last. Knox County pumps the greatest 
amount of ground water and is followed by 
Rock Island, Warren, and Mercer, in that 
order (table 1). Sources of ground water 
and water-yielding properties of the rocks 
are summarized in figure 3. 

Public water supplies that have been in- 
itiated during the past 80 years are Usted 
in table 2. The decades 1890 to 1900 and 
1950 to 1960 were the periods of greatest 
development, and 12 public water supplies 
started in each of these periods are still in 
operation. 

When towns draw their public water sup- 
plies from bedrock aquifers (table 2) there 
is a correlation between the population and 



33 



the depth at which water is obtained. In 
general, larger towns use deeper sources of 
water. For example, St. Augustine in Knox 
County has a population of 201 and obtains 
water from the Keokuk-Burlington Lime- 



stone at shallow depths. The 24 towns that 
take water from the Hunton Megagroup 
(Devonian-Silurian) average 612 in popu- 
lation. The nine towns taking water from 
the Galena, Platteville, and Ancell Groups 



i%x- 



-^k 










'^<?c^^ Thickness, interval 100 feet; 50- foot line also shown 
Bedrock outcrop 



FIG. 13 — Thickness of drift (from Piskin end Bergstrom, 1967), 



34 



have an average population of 1,500. The 
average population of tov^ns whose water 
comes from the Hunton Group, Glenwood- 
St. Peter (Ancell) and other deeper forma- 
tions is 7,340. 



Drift Aquifers 

The water-bearing properties of the gla- 
cial drift vary and reflect the wide range of 
physical properties of the glacial deposits. 
The main aquifers of the drift are beds of 
sand and gravel, which occur in bedrock 
valleys, at the base of glacial till sheets, or 
interbedded between tills. 

The distribution of sand and gravel aq- 
uifers 15 or more feet thick is shown in 
figure 14. This figure is adapted from a 
map of the sand and gravel aquifers of 
Illinois that was prepared from subsurface 
data in 1965 by Kemal Piskin of the Illi- 
nois Geological Survey. 

Piskin defined buried aquifers as those 
15 or more feet thick and covered by 10 
or more feet of overburden. Surficial aq- 
uifers were defined as those 15 or more 
feet thick and covered by less than 10 feet 
of overburden. Although all known water- 
bearing materials that meet these criteria 
were included in figure 14, other deposits 
may exist in the area. Aquifers less than 
1 5 feet thick are known to be present, but 
were not shown on the map. 

The drift aquifers are most commonly 
associated with bedrock valleys (fig. 12) 
where the drift is 50 or more feet thick 
(fig. 13). Because sand and gravel aquifers 
are more likely to occur in bedrock valleys 
where the drift is thickest, the areas in 
which the drift is more than 100 feet thick 
are shown in figure 14 as having somewhat 
favorable ground-water conditions. Aqui- 
fers other than those mapped may be pres- 
ent. Drift aquifers are generally rare over 
bedrock uplands where the drift is less than 
50 feet thick. 

Of the 84 townships within the area of 
study, 67 contain known drift aquifers at 
least 15 feet thick (fig. 14). These aquifers 
range from extremely local occurrences, ap- 
parently restricted to less than a square 



mile, to extensive deposits several miles 
wide and at least 15 miles long. 

The map (fig. 14) shows more buried 
drift aquifers than surficial aquifers in the 
area. They vary considerably in lateral ex- 
tent and occur at various depths. Surficial 
aquifers are less common in the study area 
because many of the valleys are small and 
do not contain permeable deposits as thick 
as 15 feet. However, surficial aquifers are 
extensive in such large buried valleys as 
the Green River Lowland of northern 
Henry County and the Ancient Mississippi 
Valley of northern Rock Island County. 
These valleys were glacial drainageways 
along which thick and extensive layers of 
sand and gravel were deposited, and they 
are probably the only areas in which yields 
of several hundreds of gallons of water a 
minute are available from sand and gravel. 
Only low (sometimes a gallon or two per 
minute) to moderate yields can be obtained 
from the drift in most of the region. Test 
drilling would commonly be required to 
determine the presence of permeable de- 
posits. Where water-yielding deposits of 
sand and gravel are very thin or absent, 
shallow wells of the dug type may obtain 
water from the drift by penetrating the loess 
and underlying till. In areas of less than 
50 feet of drift (fig. 13), some wells reach 
the top of bedrock and obtain water that 
seeps through gravelly material at the base 
of the drift. 

Water from sand and gravel aquifers is 
usually not highly mineralized, but it is 
fairly hard and occasionally has a high iron 
content, as shown by the following analyses 
of water from the four municipalities that 
obtain supplies from sand and gravel aq- 
uifers (Hanson, 1950, 1958, 1961) (p. 35). 

The relatively high mineralization of the 
water at Geneseo and Yates City is prob- 
ably due to the proximity of Pennsylvanian 
bedrock. 



Shallow Bedrock Aquifers 

The term "shallow bedrock aquifers," as 
used in this report, refers to water-yielding 
rocks above the Maquoketa Group. The 



35 



Water Analyses for Four Municipalities 





Gales- 




Rose- 


Yates 




burg 


Geneseo 


ville 


City 


Total dissolved 










minerals 


210 


840 


235 


329 


(ppm) 










Hardness 










(as CaCOs) 


184 


660 


148 


307 


(ppm) 










Sulfate 


— 


272.3 


45.7 


32.5 


(ppm) 










Chloride 


3.0 


49.0 


11.0 


6.0 


(ppm) 










Iron 


0.5 


1.5 


0.2 


Tr 


(ppm) 










op 


53.5 


52.0 


54.8 


53.8 



rocks belong to the Pennsylvanian, Missis- 
sippian, Devonian, and Silurian Systems 
(fig. 3). The principal aquifers within the 
shallow bedrock are the Keokuk-Burling- 
ton Limestone of Mississippian age and 
dolomite of the Silurian Niagaran Series. 

In most of the region, rocks of Pennsyl- 
vanian age are the uppermost bedrock. 
Relatively impermeable shale is the dom- 
inant rock type, but some interbedded sand- 
stones and limestones may be water-yield- 
ing, especially where they are fractured or 
jointed. The sandstones are generally fine 
grained (Wanless, 1929, 1957) and have 
low permeabilities. Many are discontinu- 
ous in areal extent and quite varied in thick- 
ness. Consequently, their potential as a 
source of ground-water supply is less than 
that of some of the deeper bedrock units, 
and their presence at specific drilling sites 
is difficult to predict. 

The Keokuk-Burlington Limestone un- 
derlies southern Warren and Knox Coun- 
ties, or approximately the southern quarter 
of the area of study (fig. 4), and is the 
source of water for many farm wells and 
for at least one public water supply. Wells 
less than 250 feet deep penetrating the 
Keokuk - Burlington generally encounter 
water in fractures, solution channels, or in 
a zone of chert rubble at the top, directly 
below the overlying shale. The quantity of 
water obtainable depends on the distribu- 



tion and interconnections of the openings 
but is generally suitable for small to medium 
supplies. The limestone probably has more 
water-filled openings where it is not over- 
lain by Pennsylvanian rbcks, in western 
Warren County, for example. Wells drilled 
within a few miles of the northern limit 
of the Keokuk-Burlington may encounter 
thin sections of limestones that will not yield 
water for extended periods of pumping. The 
northern limit of the limestone is probably 
somewhat more complex than is shown in 
figure 4. 

An analysis of water from the Keokuk- 
Burlington Limestone at Kirkwood showed 
503 parts per million (ppm) total dis- 
solved minerals, 434 ppm hardness (as 
CaCOg), 21.6 ppm sulfate, a trace of chlo- 
ride, and 1.7 ppm iron (Hanson, 1950). 
Water is more highly mineralized to the 
southeast, where the formation is deeper. 
In Peoria County, water in the Keokuk- 
Burlington contains 8,000 ppm total dis- 
solved minerals, with 4,500 ppm chloride 
(Horberg, Suter, and Larson, 1950, p. 
116). 

Devonian and Silurian carbonate rocks 
(limestone and dolomite) underlie most of 
the area of study. The Devonian limestones, 
which are thickest on the west side of the 
area, are generally tight and contain few 
water-bearing openings. They are gener- 
ally less pure than, for example, the Ni- 
agaran, and solution openings are not abun- 
dant. At least one exception to this gen- 
eralization is at Seaton, Mercer County, 
which obtains its supply from the Devonian 
at a depth of 244 feet. However, a thick 
bed of sand and gravel that overlies the 
Devonian there may contribute to the res- 
ervoir capacity of the limestone. 

The dolomite of the lower Silurian Al- 
exandrian Series also has a relatively poor 
potential for ground-water supply, being 
commonly argillaceous and having few 
openings. The Alexandrian Series under- 
Hes all of the area except for a very 
restricted area in southwestern Warren 
County (fig. 4). 

The dolomite of the Niagaran Series is 
the most dependable shallow bedrock aq- 



36 







h-^K^-^-'Mx^ 



Surficial aquifers at least 15 feet thick and overlain by less than 
^ 10 feet of overburden 



Buried aquifers at least 15 feet thick and overlain by more than 
10 feet of overburden 

Drift at least 100 feet thick; nnay contain sand and gravel aquifers 
Sand and gravel aquifers probably thin or absent 



Bedrock outcrop 



FIG. 14 — Sand and gravel aquifers (adapted from a map by Kemal Piskin). 



37 



uifer in this area. The upper 100 to 150 
feet of the Niagaran is generally well crev- 
iced and water is available for small to 
medium supplies from wells that range from 
about 400 feet deep in the north to 750 
feet deep in the southeast corner of the 
region. Most of the 25 public water sup- 
plies listed in table 2 that take water from 
the Hunton Megagroup (Devonian-Silu- 
rian) depend upon the Niagaran. Wells 
are commonly cased through the Pennsyl- 
vanian and Mississippian shales and are 
left open in the limestone and dolomite. 
Many weUs that terminate in Ordovician 
and Cambrian sandstones are left uncased 
in the Devonian and Silurian rocks, from 
which some contribution to the total yield 
is obtained. 

The distribution of the Niagaran and that 
of the Keokuk-Burlington Limestone, the 
other main shallow bedrock aquifer, com- 
plement each other. The Niagaran, which 
is well developed in the central and north- 
ern part of the study area, is thin or ab- 
sent southwest of central Warren County. 
The Keokuk-Burlington is thin in central 
and northern Warren County where it over- 
laps the Niagaran, and it thickens to the 
southwest where the Niagaran is absent. 
Thus, at least one of the two rock units is 
present throughout the study area. Yields 
of the Niagaran rocks are usually greater 
than those of the Keokuk-Burlington. 

Csallany and Walton (1963, table C) 
presented the results of pumping tests on 
wells open to the Devonian, Silurian, and 
Maquoketa. For 15 tests in the area of 
study, the average pumping rate was 95 
gpm; the rate of three tests was more than 
150 gpm; and two tests pumped less than 
30 gpm. The average adjusted specific 
capacity per foot of penetration was 0.017 
gpm per foot of drawdown; in three tests 
it was more than 0.030 gpm; and in six 
it was less than 0.010 gpm. If an average 
adjusted specific capacity of 0.017 gpm 
per foot of drawdown per foot of pene- 
tration is assumed, a well that penetrated 
250 feet into the aquifer and was pumped 
to produce 50 feet of drawdown would yield 
212 gpm. 



Csallany and Walton (1963, table B) 
also gave the results of pumping tests on 
wells open only to the Silurian. For 21 
tests in the area of study, the average pump- 
ing rate was 109 gpm; in four tests it was 
more than 200 gpm, and in three it was 
less than 30 gpm. The average adjusted 
specific capacity per foot of pentration was 
0.034 gpm per foot of drawdown; in three 
tests it was more than 0.040 gpm, and in 
six tests less than 0.010 gpm. If the same 
penetration and drawdown figures used 
above and a specific capacity of 0.034 gpm 
are applied, a well in the Silurian would 
yield 424 gpm. According to these data, 
wells open only to the Silurian have a higher 
average pumping rate, maximum pumping 
rate, and average adjusted specific capacity 
per foot of penetration than do the wells 
open to the Devonian, Silurian, and Maquo- 
keta. Perhaps the best explanation for this 
seeming paradox is the relation between 
the geographic distribution of wells in the 
study area and the distribution of the De- 
vonian and Silurian strata. Most of the 
wells reported in Csallany and Walton's 
table B (Silurian only) are in the northern 
and eastern parts of the area where the 
relatively impermeable Devonian is thin or 
absent and where the Niagaran Series of 
the Silurian is thickest. In contrast, many 
of the wells in Csallany and Walton's table 
C are in the southern and western parts of 
the area where the thickness relations are 
reversed. In general, the Silurian appears 
to be more permeable where the overlying 
Devonian is thin or absent. 

Water analyses for 21 public water sup- 
plies obtained from the Devonian-Silurian 
(Hunton) rocks were compiled, by county, 
from Hanson (1950, 1958, 1961). The 
analyses show that water is least mineralized 
in Rock Island and Henry Counties where 
the rocks are shallowest, intermediately 
mineralized in Mercer County, and most 
highly mineralized in Knox County where 
the rocks are deepest, as illustrated by the 
averages shown on page 40. 

The mineralization of water from the 
Devonian-Silurian rocks not only increases 
to the southeast in the study area but 



38 



Analyses of Water from Devonian-Silurian Rocks 





Rock 
Island 


Henry 


Mercer 


Knox 


Public 
water 
supplies 


5 


3 


6 


7 


Total 

dissolved 
minerals 
(ppm) 


329 


361 


687 


1233 


Hardness 
(as CaCOs) 
(ppm) 


184 


248 


197 


94 


Sulfate 
(ppm) 


13 


14 


83 


178 


Chloride 
(ppm) 


21 


3 


86 


228 


Iron 
(ppm) 


0.5 


0.5 


1.4 


1.2 



continues to increase southeast of Knox 
County. Horberg, Suter, and Larson (1950, 
p. 116) found that the Silurian rocks in 
Peoria County yielded water with a total 
dissolved minerals count of 3,500 ppm. 



Deep Bedrock Aquifers 

The term "deep bedrock aquifers," as 
used in this report, refers to those below 
the Ordovician Maquoketa Group. In these 
aquifers sandstones are the major water- 
yielding beds, but some creviced dolomites 
also yield water. Shales within the Maquo- 
keta Group, Glenwood-St. Peter Sand- 
stone, and Eau Claire Formation retard 
water movement and are not sources of 
water for wells. The shales sometimes cause 
problems in well construction because of 
their tendency to cave. The shales of the 
Maquoketa Group and the lower unit of 
shale and chert (Kress) in the Glenwood- 
St. Peter Sandstone frequently must be 
cased off. Other Cambrian and Ordovician 
rocks are usually left uncased. 



DOLOMITE AQUIFERS 

The major dolomite units are the Galena, 
Platteville, and Prairie du Chien Groups 



and the Eminence and Potosi Formations. 
Of the 23 recorded test holes and wells that 
end in the Galena or Platteville, at least 
13 were structure or oil tests. CsaUany 
and Walton (1963, table D) gave specific 
capacity data for five pumping tests con- 
ducted on three wells in the Galena-Plat- 
teville in the area of study; data for eight 
pumping tests on six wells in the Galena- 
Platteville located in adjacent counties also 
are given. The average adjusted specific 
capacity per foot of penetration for the nine 
wells is 0.029 gpm per foot of drawdown 
and the range is from 0.003 to 0.073 gpm. 
The average pumping rate for the 13 tests 
is 145 gpm. If the average adjusted spe- 
cific capacity is 0.029 gpm/ft in a well that 
penetrates 250 feet of the Galena-PlatteviUe 
and the well is pumped to produce 50 feet 
of drawdown, the yield would be 237 gpm. 

Several wells in the area have ended in 
the Prairie du Chien, and a few in the Rock 
Island area have ended in the Potosi Dolo- 
mite and Franconia Formation. Most of the 
wells that end in dolomite units below the 
Glenwood-St. Peter Sandstone are thought 
to draw more water from the New Rich- 
mond Sandstone and the Momence Sand- 
stone Member of the Eminence Formation 
than from the dolomite. Not enough quan- 
titative information is available for an ade- 
quate analysis. 

The quahty of the water obtained from 
the few wells that may draw most of their 
water from one of the major dolomite units 
below the Maquoketa has not been directly 
determined. By inference, water in the 
Galena-PlatteviUe is more highly mineral- 
ized than water in the Glenwood-St. Peter. 



SANDSTONE AQUIFERS 

The sandstone aquifers include the Glen- 
wood-St. Peter, the New Richmond Sand- 
stone, the Momence Sandstone Member of 
the Eminence, the Ironton-Galesville Sand- 
stone, and the Mt. Simon Sandstone. As 
many wells that penetrate these units are 
uncased below the Maquoketa, the yield of 
individual aquifers is difficult to determine. 



39 



Glenwood—St* Peter Sandstone 

The Glenwood-St. Peter Sandstone is 
the most widely used sandstone aquifer in 
the area. At least 88 wells or test holes 
pentrate part or all of it, making it one of 
the main sources of large ground-water sup- 
plies in the region. 

Within the area where the middle shale 
(Kingdom Member) of the Glenwood-St. 
Peter is well developed, five test holes 
and/or wells of record apparently do not 
penetrate the shale but terminate in the 
upper sandstone (Starved Rock Member). 
The upper sandstone thins to the north up 
the regional slope and possibly wedges out. 

Data are not available on the water- 
yielding capacity of the upper sandstone 
unit or on the quality of its water, as most 
wells that reach the upper sandstone are 
also open to higher formations. 

Within the area where the middle shale 
is well developed, several wells are open to 
both the major sandstone units of the Glen- 
wood-St. Peter, as well as to higher beds. 
Well No. 1 at Carbon Cliff, Rock Island 
County (Appendix, log 6), is considered 
representative of wells that draw from both 
sandstones and the higher beds. The well 
was cased to 623 feet, leaving it open to 
the Galena-Platteville and Glenwood-St. 
Peter. After 20 Vi hours of pumping at 608 
gpm, the drawdown was 135 feet (Hanson, 
1958). The water contained 1,707 ppm 
total dissolved solids, 450 ppm hardness 
(as CaCOg), 310 ppm sulfate, 630 ppm 
chloride, and 0.6 ppm iron. 

Water from a well at Viola where only 
the lower 98 feet of the Platteville and 127 
feet of Glenwood-St. Peter were uncased 
contains 1,104 ppm total dissolved soUds, 
210 ppm hardness (as CaCO,), 297.7 ppm 
sulfate, 260 ppm chloride, and 0.1 ppm 
iron (Hanson, 1950). The difference in 
water quality between the Carbon Cliff and 
Viola wells supports observations that the 
water quality of Glenwood-St. Peter wells 
improves as the Galena-Platteville section 
is cased out, which indicates that water in 
the Galena-Platteville is more highly min- 
eralized than water in the Glenwood-St. 
Peter. 



The pumping rates for thirteen wells open 
to the Galena-Platteville and Glenwood- 
St. Peter (Walton and Csallany, 1962) av- 
erage 247 gpm; the average adjusted spe- 
cific capacity of these wells is 3.10 gpm/ft. 
The pumping rates for tests for wells open 
only to the Glenwood-St. Peter average 
202 gpm; the average adjusted specific 
capacity of these wells is 2.50 gpm/ft. Ob- 
viously, the Galena-Platteville section con- 
tributes a significant quantity of water to 
Glenwood-St. Peter wells. 



New Richmond, Eminence, Potosi, 
and Franconia Formations 

The New Richmond Sandstone and the 
dolomite and sandstone of the Eminence 
Formation (fig. 3) probably yield some 
water to all wells that penetrate them. In 
the southern part of the study area, both 
units are more dolomitic and therefore 
probably less productive. 

A well at East Moline State Hospital 
(Rock Island County, sec. 20, T. 18 N., 
R. 1 E.) apparently terminates in the New 
Richmond. Many wells in the Rock Island 
area penetrate sandy dolomite and dolomitic 
sand a short distance below the New Rich- 
mond that average 60 feet thick. This unit 
has been called the Jordan Sandstone but 
is now called the Eminence Formation in 
this area. Buhle (1935, p. 19) reported 
that water was always found in the forma- 
tion, commonly from crevices in the dolo- 
mite, and that its piezometric surface in the 
Rock Island area stood at about 560 feet 
above sea level. Some wells reaching this 
unit had natural flows of more than 200 
gallons a minute. 

At least 1 2 wells in the study area pene- 
trate the Eminence but do not reach the 
underlying Ironton-Galesville. Nine of the 
12 extend from 17 to about 100 feet into 
the Potosi Dolomite and three partially 
penetrate the Franconia Formation. 

The city of Silvis, Rock Island County, 
obtains water from a well that terminates 
in the Potosi Dolomite at a depth of 1,680 
feet. The well is cased to 672 feet. It was 



40 



tested for 5 hours at 600 gpm and had a 
drawdown of 177 feet (Hanson, 1958). 
The water contains 1,456 ppm total 
dissolved solids, 347 ppm hardness (as 
CaCOg), 338.4 ppm sulfate, 453.0 ppm 
chloride, and 0.4 ppm iron. 

The Franconia Formation probably con- 
tributes little of the ground water pumped 
in the region, as it is generally fine grained 
and has low permeability. Buhle (1935, p. 
14) reported that water from East Moline's 
old well No. 2, which was finished in the 
Franconia, was relatively low in total hard- 
ness, calcium, magnesium, and chloride, 
and he attributed the low mineral content 
to natural softening produced by glauconite 
in the Franconia. 

Irontori'Galesville Sandstone 

The Ironton-Galesville Sandstone under- 
lies the entire study area and constitutes 
the primary source of ground water for 
large supplies. Although the unit becomes 
more dolomitic to the south of the area, 
it is essentially a uniform, clean sandstone. 

Many of the wells that extend to the 
Ironton-Galesville are similar to the City 
of Abingdon No. 2 (Appendix, log 7) . The 
well is cased to 1,441 feet (through the 
Glenwood-St. Peter), and, when test 
pumped in 1946 for 1 1/3 hours at 460 
to 485 gpm, had a drawdown of 1 1 feet 
(Hanson, 1950). Water from the well con- 
tained 1 ,324 ppm total dissolved solids, 349 
ppm hardness (as CaCO.,), 565.7 ppm sul- 
fate, 160.0 ppm chloride, and 0.7 ppm 
iron. 

Walton and Csallany (1962) presented 
data for 22 pumping tests conducted on 1 1 
wells open to the Ironton-Galesville Sand- 
stone in the region. Fifteen of the tests 
were conducted on eight wells open from 
the Galena to the Ironton-Galesville, and 
the average pumping rate was 624 gpm, 
with three rates less than 400 gpm. The 
average adjusted specific capacity was 22.5 
gpm/ft, which is considerably higher than 
averages for the same interval in north- 
eastern Illinois. The remaining seven tests 
were conducted on three wells open from 



the Prairie du Chien to the Ironton-Gales- 
ville, and the average pumping rate for these 
tests was 900 gpm, with all tests above 
500 gpm. The average adjusted specific 
capacity was 37.7 gpm/ft, with two tests 
below 30.0. 



Mt. Simon Sandstone 

The Illinois Geological Survey has rec- 
ords of two water wells and two deep oil 
tests that reach the Mt. Simon Sandstone 
in the region. The water wells are located 
in sec. 17, T. 14 N., R. 3 W., Mercer 
County, and in sec. 8, T. 17 N., R. 1 W., 
Rock Island County. The oil tests are in 
sec. 8, T. 17 N., R. 1 E., Rock Island 
County, and in sec. 30, T. 16 N., R. 1 
E., Henry County. Two other wells extend 
into the lower sandy zone of the Eau 
Claire but probably do not enter the Mt. 
Simon. The deep test in Henry County 
(Appendix, log 1 ) fully penetrates the Mt. 
Simon, whose thickness at that site is 1,255 
feet; the Mt. Simon penetration of the other 
wells ranges from 28 to 960 feet. 

The original well drilled for Aledo in 
the late 1880's penetrated the Mt. Simon 
about 5 feet to a total depth of 3,114 feet. 
A generalized log of the well (Appendix, 
log 8) was compiled from the drillers log 
and samples of well cuttings. 

Leverett (1899, p. 622) reported that 
water from the well "was not markedly 
saline until a depth of 2,620 feet had been 
reached. The temperature is 68° F." The 
depth Leverett mentions approximates the 
top of the Mt. Simon. 

An analysis of water from the well 
showed the following constituents (Hanson, 
1950) — total minerals, 432.787 grains per 
gallon (7,424 ppm); calcium sulfate, 
88.280 grains (1,511 ppm), and sodium 
chloride, 269.874 grains (4,627 ppm). 

Because the water was so highly mineral- 
ized, the well was back-filled to a depth of 
1,450 feet into the New Richmond Sand- 
stone. The well was cased only to the top 
of bedrock. In 1907, water from this well 
was reported to have a total mineral con- 



41 



tent of 2,592 ppm; in 1918, 1,746 ppm; 
and in 1932, 1,673 ppm. 

An oil test by Moline Oil and Gas Com- 
pany reached the top of the Mt. Simon 
at a depth of 2,300 feet in sec. 8, T. 17 
N., R. 1 E., Rock Island County. A water 
sample from a depth of 3,100 feet con- 
tained 5,501 ppm total dissolved solids, 
1,224 ppm total hardness (as CaCO,), 922 
sulfate, and 2,224 ppm chloride (Buhle, 
1935, table 1). A well drilled for the Tri- 
City Railway Company in Prospect Park. 
Moline (sec. 8, T. 17 N., R. 1 W., Rock 
Island County) is reported to have pene- 
trated 28 feet of Mt. Simon Sandstone be- 
low a depth of 2,340 feet, but was aban- 
doned because the water was highly min- 
eralized (Buhle, 1935, p. 6). 

Although data on the quality of the 
ground water of the Mt. Simon are limited, 
they all suggest that the water is too highly 
mineralized for most purposes. 

Recharge and Ground-Water 
M^ovement 

Ground water moves by the force of 
gravity from places of intake or recharge 
to lower places of discharge. The energy 
ground water possesses at a certain place 
by virtue of its level or pressure is called 
the hydraulic head. Ground water moves 
in the direction of lower head, and this is 
the hydraulic gradient. 

Although the principal movement of 
ground water is laterally through permeable 
beds, movement transverse to beds takes 
place where head decreases in that direc- 
tion. For example, if water above a rela- 
tively impermeable confining bed is under 
greater head than the water in the confined 
aquifer below, the water above will perco- 
late into the lower aquifer; if it is under 
less head, the water in the lower aquifer 
will escape upward. 

Data on head relations — as expressed by 
water levels under nonpumping and pump- 
ing conditions — are necessary for determin- 
ing the pattern of ground-water movement. 
However, reports on water levels, hydrauhc 



gradients, hydraulic properties, or water 
quality of individual deep aquifers in the 
area of this report have been few because 
most deep wells are open to, and obtain 
water from, several aquifers. In some deep 
wells the Devonian-Silurian rocks also are 
left uncased, further reducing the opportun- 
ity for obtaining specific data on the deep 
aquifers. Because of the lack of data, the 
hydrology of the deeper rocks is not well 
known, and generalizations on ground- 
water movement, recharge, and discharge 
must be somewhat speculative. 

More is known about the general move- 
ment of ground water in the shallow rocks 
— the glacial drift and Pennsylvanian, and, 
in the western and northern parts, the Mis- 
sissippian, Devonian, and Silurian. Water 
in these rocks probably circulates in shal- 
low flow systems, entering the ground from 
precipitation in upland areas, then perco- 
lating downward and flowing laterally to 
discharge along drainage lines. It is known 
from studies of areas in northeastern Illinois 
(Williams, 1966) that the paths of water 
movement in the drift are often extremely 
shallow and short. Commonly, water en- 
ters the drift along stream divides and dis- 
charges a few hundred to a few thousand 
feet away along minor tributary or major 
streams. 

As the upper bedrock formations are 
mainly dense shales and limestones, most 
water enters them through joints and frac- 
tures. The pattern of ground-water move- 
ment through the Pennsylvanian rocks and 
the New Albany Shale is complex. Some 
water enters fracture zones on narrow up- 
lands and discharges in nearby vaUeys 
through permeable beds or at the tops of 
tight shale beds. Where the uplands are 
broad and flat, much of the water entering 
the fractures percolates downward to lower 
formations, and only along the sides of the 
uplands does water move toward the val- 
leys. The shales also confine underlying 
permeable beds and permit the develop- 
ment of artesian pressures. For example, 
in the southern third of the area (fig. 5), 
the Pennsylvanian shales confine the Ke- 
okuk-Burlington rocks, and in the southern 



42 



two-thirds of the area the New Albany Shale 
confines the Devonian-Silurian limestones 
and dolomites. 

Recharge to the Keokuk - Burlington 
Limestone occurs in the southern third of 
the area where the limestone crops out or 
immediately underlies the drift or where 
the overlying Pennsylvanian rocks are thin 
or cap broad flat uplands. 

The Silurian and Devonian carbonate 
rocks (Hunton) are close to land surface 
only in the northern part of the area (fig. 
5 ) , where they are recharged on the uplands 
and discharge water along the main river 
valleys — the Mississippi, Rock, and Green. 
In the southern two-thirds of the area the 
Hunton is more than three or four hundred 
feet deep and has Pennsylvanian shales and 
the New Albany Shale above it. Here water 
percolates downward to the Hunton and 
moves laterally toward the Illinois River. 
This is suggested by a few data that show 
decUning head between the Keokuk-Burl- 
ington Limestone and Silurian dolomite in 
southern Knox County, increasing mineral- 
ization of water in the Silurian in a south- 
easterly direction (Hanson, 1950, 1958, 
1961), and increase of head between the 
Keokuk-Burlington and Silurian along the 
Illinois River (Udden, 1912, p. 94). 

The Maquoketa Group retards down- 
ward percolation of water from the shallow 
aquifers and confines the water in the deep 
aquifers. It thus separates the two sys- 
tems, but does not entirely seal them. 



FLOW IN THE DEEP AQUIFERS 

Water level data on individual deep aq- 
uifers (Hanson, 1950, 1958, 1961) are 
inadequate to determine the head relations 
below the Maquoketa Group. In the early 
days of development — mainly before the 
early 1900's — flowing wells were com- 
monly obtained from rocks below the Ma- 
quoketa Group where land surface was 
below an elevation of about 630 feet above 
sea level. The flow commonly increased 
as the Galena-Platteville, Glenwood-St. 



Peter, New Richmond, Eminence, and Iron- 
ton-Galesville rocks were successively pene- 
trated. In a few weUs, measurements indi- 
cated that the hydraulic head increased 
downward, but in many others it is not 
known whether increased head or penetra- 
tion of more permeable rocks, or both, 
caused the increased flows. In the adjacent 
Peoria region, flowing wells from the Sil- 
urian, Galena-Platteville, and Glenwood- 
St. Peter rocks were obtained below a sur- 
face elevation of about 600 feet (Udden, 
1912, p. 94). 

With the introduction of pumping, ar- 
tesian head declined, particularly in the 
Glenwood-St. Peter Sandstone, the most 
heavily developed aquifer. By the 1920's, 
the artesian head had fallen well below a 
600-foot elevation at most places (Hanson, 
1950, 1958, 1961).Buhle (1935) reported 
that the Jordan Sandstone (Eminence) then 
still supported flowing wells at some loca- 
tions in the Rock Island area. Head in 
formations as deep as the Ironton-Galesville 
Sandstone has continued to decline as 
a result of pumping. Today artesian head 
in the aquifers below the Maquoketa in- 
creases downward, but this is largely be- 
cause there has been less pumping of the 
deeper aquifers. 

From limited data (Hanson, 1950, 1958, 
1961, and Udden, 1912), analogy with 
northeastern Illinois (Suter et al., 1959), 
and theoretical models presented by Freeze 
and Witherspoon (1967), it is postulated 
that head relations before pumping were 
such that water below the Maquoketa 
Group flowed mainly laterally through the 
permeable sandstone aquifers and that there 
was some discharge upward through the 
Maquoketa into the Silurian rocks. The 
Freeze and Witherspoon (1967) models 
suggest that some discharge of deep flow 
systems probably occurs in major valleys, 
such as the Mississippi and Illinois, but not 
in minor valleys. Water level data in the 
Illinois Valley at Peoria (Udden, 1912, p. 
94) tend to confirm this. There is no indi- 
cation that under natural conditions any of 
the area in study was a recharge area for 
the deep rocks. 



43 



Water was probably recharged to the 
deep aquifers from topographically high 
areas in the northern part of Illinois where 
the Maquoketa Group and younger rela- 
tively impermeable rocks are absent and 
the Galena- Platte ville Group and older 
rocks crop out or underlie the glacial drift 
(Suter et al., 1959, p. 59). Movement of 
water from the recharge area in general 
probably followed the regional bedrock 
structure; that is, it moved southward and 
southeastward, with some convergence of 
flow toward the main drainages. Recharge 
and discharge areas were thus separated by 
several scores of miles, with wide areas of 
deep, essentially horizontal flow between. 

Under pumping conditions today, some 
of the water in the deep aquifers is being 
diverted toward weUs, some water in the 
underlying formations is being induced to 
flow upward in pumping centers, and some 
water in the shallow aquifers is being drawn 
downward. Some lateral flow doubtless con- 
tinues, as does upward discharge along the 
major drainage lines. 

A further consequence of the prevailing 
ground-water flow systems and the variable 
permeabilities of the rocks is the pattern 
of mineral quality variation in the ground 
water. Water percolates downward and 
then moves laterally, becoming more min- 
eralized with depth. Where the movement 
is through Pennsylvanian or New Albany 
rocks, which have low permeabilities, the 
water becomes fairly highly mineraUzed 
with depth, particularly with chlorides and 
sodium, because there has been little dilu- 
tion or flushing of even the very soluble 
salts. 

In the deep aquifers, where water is for 
the most part flowing laterally along gently 
dipping beds, the water becomes more min- 
eralized to the south and southeast and 
eventually becomes of a quality that makes 
it unsuitable for human use. Because the 
permeabilities of the Ordovician and Cam- 
brian sandstones are higher than those of 
the shallower Mississippian and Devonian- 
Silurian carbonates, a greater quantity of 
fresher water has flowed through the sand- 
stones, flushing the very soluble salts, like 



the chlorides, farther down dip. Less sol- 
uble salts, such as the sulfates, constitute 
a major part of the mineralization of these 
waters. The underflow in the deep aquifers 
has therefore produced less mineralized, 
sulfate-bearing waters under more mineral- 
ized, chloride-bearing waters. 

Where water from the deep aquifers is 
escaping upward into the Silurian rocks, as 
it possibly does along the Illinois River, 
the level of mineralization may be inter- 
mediate — one with less mineralization than 
the Keokuk-Burlington rocks but more than 
the Galena-Plattevifle and Glenwood-St. 
Peter rocks — and the amounts of chlorides 
and sulfates present may be somewhat sim- 
Uar. 



Ground-Water Conditions by 
County 

HENRY COUNTY 

Permeable sand and gravel aquifers oc- 
cur in glacial drift from 100 to more than 
300 feet thick in the Green River VaUey 
and the buried Ancient Mississippi Valley 
in the northern townships of Henry County 
(fig. 14) . Geneseo obtains water from weUs 
15 to 65 feet deep in these aquifers adja- 
cent to the Green River. A 65-foot well 
was tested at a rate of up to 605 gpm with 
a drawdown of 10.4 feet after 6V4 hours 
of pumping (Hanson, 1950). The sand 
and gravel aquifers mapped in the northern 
townships are the most favorable sources 
of large ground - water supplies in the 
county. Elsewhere, sand and gravel de- 
posits are thin and scattered and are most 
likely to be found in the tracts of thicker 
drift. 

Pennsylvanian rocks are the uppermost 
bedrock in most of the county, attaining a 
maximum thickness of about 300 feet. 
Sandstones and fractured limestones and 
shales in the Pennsylvanian yield sufficient 
water for domestic supplies in some places. 
The chances of obtaining a well in Pennsyl- 
vanian rocks with a yield exceeding 1 5 gpm 
are poor (Csallany, 1966, p. 36). 



44 



Dolomite of Silurian age, ranging in 
thickness from about 250 feet in the south 
to more than 400 feet in the north, is the 
main source of domestic ground-water sup- 
plies and the source of municipal supply 
at Andover, Annawan, Bishop Hill, Colona, 
and Orion. The upper 125 feet of the rock 
is the most favorable water-yielding zone. 
Wells in the Devonian-Silurian must be 
projected for depths ranging from 400 feet 
in the northern part of the county to 700 
feet in the southern part. 

The Glenwood-St. Peter Sandstone is 
the next important aquifer below the Sil- 
urian dolomite. Along with the Devonian- 
Silurian and Galena-Platteville Dolomite, it 
provides municipal water supply for Alpha, 
Atkinson, Cambridge, Galva, and Wood- 
hull. Wells to the Glenwood-St. Peter are 
some 1,500 feet deep at Galva and Ke- 
wanee. 

The deepest aquifer penetrated in the 
county is the Ironton-Galesville Sandstone 
at Kewanee, where it occurs at a depth of 
about 2,450 feet. Water development dur- 
ing the past 80 years at Kewanee has shown 
that wells drilled to the Glenwood-St. 
Peter commonly yield about 200 gpm of 
water with approximately 1,200 ppm total 
dissolved minerals, whereas wells to the 
Ironton-Galesville yield 600 to 900 gpm of 
water with about 1,700 ppm total dissolved 
minerals (Hanson, 1950). 



KNOX COUNTY 

Water-yielding sand and gravel deposits 
are rare beneath the upland, where the drift 
is less than 50 feet thick and bedrock crops 
out intensively (fig. 13). Some sand and 
gravel aquifers that are mainly suitable for 
small supplies occur along the valley of 
Cedar Creek at and west of Galesburg and 
along Spoon River in the southern part of 
Knox County (fig. 14). Testing is neces- 
sary to locate suitable well sites. For ex- 
ample, at Yates City a test a mile east of 
the village revealed a deposit of sand and 
gravel some 30 feet thick overlying bed- 
rock at a depth of 85 feet; the lower 11 



feet, when developed, yielded 100 gpm with 
2 feet of drawdown (Hanson, 1950). 

The Pennsylvanian rocks range from 
about 50 to 300 feet thick in the county and 
yield a few small ground-water supplies 
locally. Most wells go through them to 
penetrate deeper aquifers. The Keokuk- 
Burlington Limestone is a fairly dependable 
aquifer for farm supplies in the southern 
third of the county, with wells ranging from 
about 250 to 350 feet deep. Water in the 
Keokuk-Burlington is probably quite highly 
mineralized in the southeastern corner of 
the county. 

The Silurian dolomite is better creviced 
than the Keokuk-Burlington Limestone and, 
being deeper, is capable of somewhat 
greater yields. It and the overlying Devo- 
nian limestone are the source of seven pub- 
lic water supplies in the county (table 2). 
Wells range from about 600 to 900 feet 
deep. The Silurian thickens from less than 
90 feet to almost 300 feet between the 
southwestern and northeastern corners of 
the county, whereas the Devonian limestone 
averages about 90 feet. 

The deep bedrock aquifers, principally 
the Glenwood-St. Peter and Ironton-Gales- 
ville, are sources of large ground-water sup- 
plies and are developed at Abingdon and 
Knoxville; they formerly were used at 
Galesburg. Wells to the Ironton-Galesville 
are about 2,500 feet deep. A log and 
water analysis from the Abingdon well are 
given in log 7 of the Appendix. 



MERCER COUNTY 

Deposits of sand and gravel are exten- 
sive in Mercer County only along the Mis- 
sissippi River. They are thin and discon- 
tinuous in some of the tributaries of the 
Mississippi in the nine eastern townships 
of Mercer County considered in this re- 
port (fig. 14). Locally, within the areas 
where the drift exceeds 200 feet thick, sand 
and gravel deposits suitable for drilled wells 
are present. 

Most farm wells are finished in the De- 
vonian-Silurian rocks and a few in Pennsyl- 



45 



vanian sandstones or fractured shales, lime- 
stones, or coal. Six public supplies (table 
2 ) are obtained from the Devonian-Silurian 
rocks, with wells ranging from 250 to 650 
feet deep and averaging 400 to 500 feet 
deep. 

The Glenwood-St. Peter Sandstone is 
the deepest aquifer in use for public water 
supply. It is penetrated by wells 1,200 and 
1,280 feet deep at Aledo and Viola. The 
Ironton-Galesville Sandstone, which could 
be penetrated in wells about 2,400 feet 
deep, represents a possible additional source 
of ground water. 



most hkely to occur in the upper 125 feet 
of the dolomite, but the overlying Devonian 
limestone and the lower part of the Silurian 
dolomite are commonly tight and not water- 
yielding. Five public water supplies are ob- 
tained from the Silurian and Devonian 
rocks. 

Of the deep aquifers, the Glenwood- 
St. Peter, Eminence, and Ironton-Galesville 
have supplied water for municipal and in- 
dustrial purposes in Rock Island County, 
with wells from 1,100 to 2,100 feet deep. 
At present, only Carbon Cliff and Silvis 
have deep wells; the larger cities obtain 
public supplies from the Mississippi River. 



ROCK ISLAND COUNTY 

Sand and gravel aquifers along the Mis- 
sissippi River are thin and limited in areal 
extent in most of Rock Island County be- 
cause the river south of Cordova flows 
through a rock gorge. North of Cordova, 
in the two northern townships, extensive 
and fairly thick sand and gravel deposits 
occur along the ancient course of the Mis- 
sissippi. This tract extends eastward (fig. 
14) to the bend of the Illinois River at 
Hennepin in Putnam County; it is one of 
the main areas of favorable but undevel- 
oped ground- water resources in the state. In 
the sandy tract north of Cordova, alluvial 
deposits, containing considerable sand and 
gravel, are from about 40 to more than 
200 feet thick. 

Sand and gravel deposits along the Rock 
River are thin and scattered. The glacial 
drift thickens to more than 100 feet in the 
southeastern townships and contains local 
beds of sand and gravel. 

Some domestic wells obtain small sup- 
plies of water from sandstone, coal, or 
fractured shale in the Pennsylvanian rocks 
that attain a maximum thickness of about 
100 feet. However, most wells are drilled 
through the Pennsylvanian and Devonian 
rocks and are completed in the Silurian 
dolomite. The Silurian is reached at depths 
ranging from a few feet in the northern part 
of the county to about 400 feet in the south- 
eastern corner. Water-filled fractures are 



WARREN COUNTY 

Thin sand and gravel deposits in Warren 
County are penetrated at many places in 
the glacial drift, which attains a maximum 
thickness of about 135 feet. The thicker 
deposits occur along belts bordering Hen- 
derson and Cedar Creeks (fig. 14). Rose- 
ville, with three wells 20 to 35 feet deep, 
has the only public water supply in the 
county drawn from the glacial drift. 

Wells in the Pennsylvanian rocks are 
common in the eastern townships of the 
county where sandstones yield water in the 
depth range of 35 to 150 feet. In the south- 
ern two-thirds of the county many wells 
are finished in the Keokuk - Burlington 
Limestone. The average thickness of the 
Keokuk-Burlington is 100 feet, and the 
range is from 5 to 155 feet; the average 
depth to the top of the limestone is about 
140 feet. Where the Keokuk-Burlington 
is absent, wells generally go to the Silurian 
dolomite. In the southwestern quarter of 
the county where the Niagaran rocks are 
absent, wells are either completed in the 
Keokuk-Burlington or in the deeper aq- 
uifers. 

Alexis and Kirkwood have wells that 
reach the Glenwood-St. Peter Sandstone 
at depths of about 1,200 feet, and the Mon- 
mouth wells are finished in the Ironton- 
Galesville Sandstone at depths of about 
2,400 feet. 



46 



CONCLUSIONS 

1. A variety of ground-water sources 
are available v^ithin the Rock Island, Mon- 
mouth, Galesburg, and Kewanee area, in- 
cluding drift aquifers, shallow bedrock aq- 
uifers, and deep bedrock aquifers. They 
provide about half of the total water 
pumped in the area, the remainder being 
drawn from surface sources. 

2. Drift aquifers are generally thin and 
of limited extent in most of the area of 
study. Where they do occur, many are suit- 
able for small water supplies. 

3. Thick deposits of permeable sand 
and gravel in the drift occur only in north- 
ern Rock Island and Henry Counties and 
are favorable sources for large water sup- 
plies. 

4. The most widespread aquifers for 
small to medium water supplies are the 
Niagaran Series dolomite and the Keokuk- 
Burlington Limestone. 

5. The principal bedrock sources of 
water for industrial and municipal supplies 
are the deep sandstone aquifers. The most 
favorable units are the Glenwood-St. Peter 



Sandstone and the Ironton-Galesville Sand- 
stone, which appear to be usable in the en- 
tire area, although their water quality is 
less favorable in the southeast. Water in 
the Mt. Simon Sandstone is probably too 
highly mineralized for most uses. 

6. Water in the drift and shallow bed- 
rock is recharged locally, whereas water 
in bedrock aquifers below the Maquoketa 
Group probably comes mainly from re- 
charge areas tens of miles to the north and 
northeast. 

7. Pumping has lowered the artesian 
head considerably in the deep bedrock aq- 
uifers, particularly in the Glenwood-St. 
Peter Sandstone. In the last two decades 
there has been a marked reduction in pump- 
ing from the deep aquifers in the Tri-Cities 
and at Galesburg as more supplies have 
been developed from the Mississippi River 
or shallow aquifers. 

8. In the future it is likely that smaller 
municipalities will go to deeper aquifers 
as their water needs increase, and larger 
municipalities will obtain supplies from the 
Mississippi River or from areas of favor- 
able gravel aquifers. 



47 



REFERENCES 



Bell, A. H., Atherton, El wood, Buschbach, 
T. C, and Swann, D. H., 1964, Deep oil pos- 
sibilities of the Illinois Basin: Illinois Geol. 
Survey Circ. 368, 38 p. 

Bergstrom, R. E., 1956, Ground-water geology 
in western Illinois, north part — ^A preliminary 
geologic report: Illinois Geol. Survey Circ. 
222, 24 p. 

Bradbury, J. C, and Atherton, Elwood, 1965, 
The Precambrian basement of Illinois: Ilhnois 
Geol. Survey Circ. 382, 13 p. 

Buhle, M. B., 1935, Ground-water supplies in 
the vicinity of the Tri-Cities, Davenport, Iowa; 
Rock Island and Mohne, Illinois: State Uni- 
versity of Iowa unpublished M. S. thesis; Ilh- 
nois Geol. Survey unpubhshed rept. MBB-1 on 
open file. 

BuscH, W. L., 1967, lUinois mineral production 
by counties, 1965: Illinois Geol. Survey Min. 
Ec. Brief 16. 10 p. 

Buschbach, T. C, 1964, Cambrian and Ordovi- 
cian strata of northeastern Illinois: Illinois 
Geol. Survey Rept. Inv. 218, 90 p. 

Buschbach, T. C, 1965, Deep stratigraphic test 
well near Rock Island, Illinois: Illinois Geol. 
Survey Circ. 394, 20 p. 

CoLLiNsoN, Charles, 1961, The Kinderhookian 
Series in the Mississippi Valley: Kansas Geol. 
Survey 26th Ann. Field Conf. Guidebook, p. 
100-109; Illinois Geol. Survey Reprint 196 1-U. 

Csallany, Sandor, 1966, Yields of wells in 
Pennsylvanian and Mississippian rocks in Illi- 
nois: Illinois Water Survey Rept. Inv. 55, 43 p. 

Csallany, Sandor, and Walton. W. C, 1963, 
Yields of shallow dolomite wells in northern 
Illinois: Illinois Water Survey Rept. Inv. 46, 
43 p. 

Emrich, G. H.. 1966, {ronton and Galesviile 
(Cambrian) Sandstones in Illinois and adja- 
cent areas: Illinois Geol. Survey Circ. 403, 
56 p. 

Foster, J. W., 1956, Ground-water geology of 
Lee and Whiteside Counties, Ilhnois: lUinois 
Geol. Survey Rept. Inv. 194, 67 p. 

Freeze, R. A., and Witherspoon, P. A., 1967, 
Theoretical analysis of regional ground-water 
flow; 2. Effect of water-table configuration and 
subsurface permeability variation: Am. Geo- 
phys. Union Water Resources Research, v. 3. 
no. 2, p. 623-634. 

Frye, J. C, WiLLMAN, H. B., and Black, R. F., 
1965, Outline of glacial geology of Illinois and 
Wisconsin. /// Wright, H. E., Ir., and Frey, D. 
G. (editors). The Quaternary of the United 



States: Princeton University Press, Princeton, 
N. J., p. 43-61; Illinois Geol. Survey Reprint 
1965-N. 

Hanson. Ross (compiler), 1950, 1958, 1961, 
Public ground-water supplies in Illinois: Illi- 
nois State Water Survey Bull. 40 and supple- 
ments. 

Harvey, R. D., 1964, Mississippian limestone re- 
sources in Fulton, McDonough, and Schuyler 
Counties, Illinois: Illinois Geol. Survey Circ. 
370, 27 p. 

HoRBERG, Leland, 1946, Preglacial erosion sur- 
faces in Illinois: Jour. Geology, v. 54, no, 3, p. 
179-192; reprinted as Illinois Geol. Survey 
Rept. Inv. 118, 20 p. 

Horberg, Leland, 1950, Bedrock topography of 
Illinois: Illinois Geol. Survey Bull. 73, 111 p. 

Horberg, Leland, 1956, Pleistocene deposits 
along the Mississippi Valley in central-western 
Illinois: Illinois Geol. Survey Rept. Inv. 192, 
39 p. 

Horberg, Leland, Suter, Max, and Larson, T. 
E., 1950, Ground water in the Peoria region: 
Ilhnois Geol. Survey Bull. 75, 128 p. 

Illinois Technical Advisory Committee on 
Water Resources, 1967, Water for Illinois: A 
plan for action: Springfield, III., 452 p. 

Leighton, M. M., Ekblaw, G. E., and Horberg, 
Leland, 1948, Physiographic divisions of Illi- 
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printed as Ilhnois Geol. Survey Rept. Inv. 129. 

Leverett, Frank, 1899, The Illinois glacial lobe: 
U. S. Geol. Survey Monograph 38, 817 p. 

Parham, W. E., 1960, Lower Pennsylvanian clay 
resources of Knox County, Illinois: Illinois 
Geol. Survey Circ. 302, 19 p. 

Parham, W. E., 1961, Lower Pennsylvanian clay 
resources of Rock Island, Mercer, and Henry 
Counties, Illinois: Illinois Geol. Survey Circ. 
322, 40 p. 

Rand McNally and Co., 1966, Rand McNally 
commercial atlas and marketing guide: 97 Lh 
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Reinertsen. D. L., 1964, Strippable coal re- 
serves of Illinois. Part 4 — Adams, Brown, Cal- 
houn, Hancock, McDonough, Pike, Schuyler, 
and the southern parts of Henderson and War- 
ren Counties: Illinois Geol. Survey Circ. 374, 
32 p. 

Ross, R. C. and Case, H. C. M., 1956, Types of 
farming in Illinois — An analysis of differences 
by areas: Univ. Ilhnois Agr. Exper. Station 
Bull. 601. 88 p. 



48 



Savage, T. E., 1922, Geology and mineral re- 
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in Yearbook for 1917 and 1918: Illinois Geol. 
Survey Bull. 38, p. 209-271. 

Savage, T. E., and Nebel, M. L., 1923, Geology 
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Savage, T. E., and Udden, J. A., 1922, The geol- 
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Smith, W. H., and Berggren, D. J., 1963, Strip- 
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Yields of deep sandstone wells in northern 
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47 p. 

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APPENDIX 



49 



1. E. A. SOUTH NO. 1 

Sample study log of the E. A. South No. 1 
well, SW SW SW sec. 30, T. 16 N., R. 1 E., 
Henry County, Illinois. Total depth 3863 feet. 
Elevation 803 feet. Illinois Geological Survey 
sample set 41427. Drilled by Ralph E. Davis, 
October 1961. Described by T. C. Buschbach. 
1964. 



Thick- 
ness Depth 
(ft) (ft) 
QUATERNARY SYSTEM 
PLEISTOCENE SERIES 

Till, silty, yellowish 

gray, leached 50 50 

Till, calcareous, yellow- 
ish orange to olive, 
oxidized, sandy at 
base 113 163 

PENNSYLVANIAN SYSTEM 

Shale, calcitic, dark 
gray, carbonaceous, 
pyritic, hard; coal; 
abundant sand, me- 
dium, uncemented, 
angular, pyritic .... 27 190 

Shale, silty, gray, brit- 
tle, micaceous; silt- 
stone, argillaceous, 
gray; some coal and 
weak, dark gray 
shale; a little sand- 
stone, light yellowish 
gray, fine, firm .... 75 265 

DEVONIAN SYSTEM 

CEDAR VALLEY FORMATION 

Dolomite, very silty, 
light brownish gray 
to light greenish gray, 
very fine 15 280 

Limestone, dolomitic, 
light grayish brown, 
gray, white, very fine 
to lithographic, part- 
ly fossiliferous; chert 
at 330-340' 100 380 

WAPSIPINICON FORMATION 
Lost circulation; no 

samples 20 400 



72 



10 



490 
500 



SILURIAN SYSTEM 
NIAGARAN SERIES 

No samples 18 418 

Dolomite, light gray, 
fine to medium, crys- 
talline, porous, vug- 
gy (reef rock) .... 

Dolomite, as above, 
pale yellowish gray 

Dolomite, light gray to 
pale yellowish gray, 
fine to medium, crys- 
talline, porous, vug- 

gy in part 100 600 

ALEXANDRIAN SERIES 

Dolomite, light gray 
t o light yellowish 
gray, fine to medi- 
um, partly porous; 
trace of glauconite . . 40 640 

Dolomite, cherty, light 
yellowish gray t o 
light gray, fine; trace 
of glauconite; a few 
weak, light green 
argillaceous streaks . 23 663 
ORDOVICIAN SYSTEM 
CINCINNATIAN SERIES 

MAQUOKETA SHALE GROUP 
BRAINARD SHALE 

Shale, silty, dolomitic, 
greenish gray; few 
dolomite streaks 690- 

700' 75 738 

FORT ATKINSON DOLOMITE 

Dolomite, silty, argilla- 
ceous, gray, fine; in- 
terbedded shale, silty, 
greenish gray; shale 
increases toward base 17 755 
SCALES SHALE 

CLERMONT MEMBER 

Shale, silty, dolomitic, 
greenish gray to 
grayish brown; inter- 
bedded dolomite in 
1-2" beds and irregu- 
lar nodules 75 830 

ELGIN MEMBER 

Shale, silty, dolomitic, 
dark brown to gray- 
ish brown; dolomite 
streaks, brown, fine; 
depauperate zone at 
base and top 40 870 



50 



107 978 



126 1104 



CHAMPLAINIAN SERIES 
GALENA GROUP 

WISE LAKE FORMATION 

Dolomite, grayish buff, 
gray mottled, fine, 
pyritic; 1" calcite 
crystals 1 871 

Dolomite, buff, medium 
to fine, porous, part- 
ly vuggy; thin red- 
dish brown shale 
partings; numerous 
gastropods 945' to 

base 

DUNLEITH FORMATION 

Dolomite, cherty, buff, 
fine to medium; rare 
thin shale partings . 
GUTTENBERG FORMATION 

Dolomite, reddish buff, 
coarse; dark reddish 
brown shale partings 
1/16-1/4" thick at 
3 - 6" intervals; 3" 
green shale at base . . 7 1111 

Wavy interbeds of do- 
le mite, brown, 
coarse; dolomite, 
gray, fine; shale, red- 
dish brown 7 1118 

PLATTEVILLE GROUP 

Limestone, brown, lith- 
ographic, dense; do- 
lomite, brown, fine; 
shale partings, red- 
dish brown; beds of 
Strophomena and V2" 
dark brown shale at 

base 

Dolomite, calcitic, gray- 
ish brown, very fine . 

Dolomite, calcitic, cher- 
ty, grayish brown, 
very fine (chert in 
1-4" nodules) 

Limestone, brownish 
gray, very fine; some 
gray "birds eye" mot- 
tling; chert nodules 

Limestone, grayish 
brown, very fine to 
coarse, fossiliferous, 
cherty in upper 10'; 
thin dark brown to 
dark gray shale part- 
ings 18 1170 

Dolomite, calcitic, gray- 
ish brown to brown, 
partly gray mottled, 
fine; limestone, dolo- 
mitic, brownish gray, 
very fine 21 1191 



ANCELL GROUP 

GLENWOOD FORMATION 

Sandstone, dolomitic, 
fine, fucoidal; many 
irregular dark gray 
argillaceous laminae; 
6" green shale at 
base 



4 1195 



14 



1132 
1137 



11 1148 



4 1152 



ST. PETER SANDSTONE 
STARVED ROCK MEMBER 

Sandstone, white, fine 
to medium, porous, 
friable, some cross 
bedding; faint green, 
argillaceous coloring; 
2' sandy green shale 
at 1218-1220' .... 35 1230 

KINGDOM MEMBER 

Shale, dark green, hard 9 1239 

TONTI MEMBER 

Sandstone, white t o 
light greenish gray, 
fine to medium, fri- 
able, porous, some 
cross bedding; few 
6-8" streaks of sand- 
stone, white, fine, 

well cemented 62 1301 

KRESS MEMBER 

Shale, bright green; 
chert pebbles; dolo- 
mite fragments .... 2 1303 

CANADIAN SERIES 

PRAIRIE DU CHIEN GROUP 
SHAKOPEE DOLOMITE 

Variable unit of dolo- 
mite, partly sandy, 
partly cherty, light 
gray to light brown- 
ish gray, very fine to 
fine, slightly glauco- 
nitic, partly vuggy; 
some relict oolitic 
structure; some thin 
green shale partings; 
some thin beds of 
sandstone, dolomitic, 
buff, medium; few 
beds of dolomite, 
coarse to medium, 
porous; chert, chalky 
to tripolitic, occurs 
as nodules and as re- 
placement networks; 
includes thin string- 
ers of sandstone in 
places; some nearly 
vertical fracturing 
1430' to base 193 1496 

Dolomite, silty, light 
grayish brown, very 



51 



fine; interlaminated 

with green shale .... 1 1497 

Dolomite, Hght grayish 

brown, very fine ... 7 1504 

Dolomite, sandy in 
lower part, light 
brown and light 
grayish brown, mot- 
tled, fine, crystalline, 
vuggy; calcite crys- 
tals in some vugs. . . 6 1510 

NEW RICHMOND SANDSTONE 
Sandstone, dolomitic, 
medium to fine, mod- 
erate sorting, sub- 
rounded to subangu- 
lar, slightly friable; 
dolomite, sandy, light 
gray to light pinkish 
gray, very fine; shale 
partings, green; 
chert, sandy, white, 
chalky, oolitic; slight 
oil stain in vug at 
1532' 47 1557 

ONEOTA DOLOMITE 

Dolomite, light grayish 

brown to light gray, 

very fine; thin glau- 

conitic films 3 1560 

Dolomite, slightly 

sandy, brownish 

gray, medium to fine, 

crystalline, partly 

vuggy; some calcite 

and drusy dolomite 

in vugs; little chert. . 20 1580 
Dolomite, cherty, light 

brownish gray, fine 

to medium, crystal- 
line, partly vuggy . . 8 1588 
Dolomite, white to 

pale yellowish 

brown, medium, por- 
ous; some soft white 

silica in vugs; a trace 

of shale, light green, 

brittle 22 1610 

Dolomite, cherty, light 

gray to light brown- 
ish gray, medium to 

fine, porous, slightly 

pyritic; some green 

shale partings; pale 

orange chert 1670- 

1680'; dolomite, very 

coarse at 1690-1700' 90 1700 
Dolomite, light brown- 
ish gray, medium to 

fine, porous, slightly 

glauconitic; dolomite, 



pink, coarse, hema- 

titic; trace of sand. . 20 1720 

Dolomite, cherty, hght 
gray to light yellow- 
ish brown, fine; some 
thin contorted beds 
of green shale 20 1740 

Dolomite, partly cherty, 
light yellowish brown 
to brown, fine to 
coarse, porous, vug- 
g y ; calcite; quartz 
crystals, drusy dolo- 
mite, and white sili- 
ceous powder in 
vugs; few green shale 
partings; some partial 
chert replacement . . 29 1769 
CAMBRIAN SYSTEM 
CROIXAN SERIES 

EMINENCE FORMATION , 

Dolomite, sandy, gray- 
ish brown to light 
brownish gray, fine to 
medium; chert, ooli- 
tic, sandy, white; thin 
stringers of s a n d - 
stone, light green, 
medium, cemented 
with white, chalky 
silica; thin stringers 
and blebs of green 
clay 11 1780 

Sandstone, dolomitic, 
white, medium, mod- 
erately sorted, sub- 
rounded, coherent . 10 1790 

Dolomite, sandy, light 
brownish gray, fine 
to medium; chert, 
sandy, oolitic, white; 
some calcite, pyrite, 
and green shale ... . 26 1816 
MOMENCE SANDSTONE MEMBER 

Sandstone, siliceous, 
dolomitic, white to 
tan, medium, poor- 
ly sorted 14 1830 

POTOSI DOLOMITE 

Poor samples — lost 

circulation 10 1840 

Dolomite, shghtly 
sandy, light grayish 
brown, fine, very 
slightly glauconitic at 
top; a little drusy 
quartz and dolomite. 
Lost circulation at 
1865' 60 1900 

Dolomite, light grayish 
brown, a little light 
pink mottling, fine. 



52 



slightly glauconitic; 
drusy quartz; some 
pyrite and calcite as- 
sociated with lost 
circulation zone at 
I960' 



96 1996 



FRANCONIA FORMATION 

Dolomite, slightly 
sandy, light gray to 
pink, fine, glauco- 
nitic 49 2045 

Sandstone, dolomitic, 
slightly argillaceous, 
greenish gray, fine, 
very glauconitic, fri- 
able, porous; shale 
partings, gray, brittle; 
a few streaks of do- 
lomite, silty, sandy, 
brownish gray, very 
fine, slightly glauco- 
nitic 102 2147 

Dolomite, light buff, 
fine, crystalline; dolo- 
mite, silty, sandy, 
gray, very fine, 
slightly glauconitic . 13 2160 

Shale, silty, green, 
brittle to weak, mi- 
caceous, slightly 
glauconitic; s a n d - 
stone, silty, grayish 
orange, very fine, 

glauconitic 17 2177 

IRONTON-GALESVILLE SANDSTONE 

Dolomite, sandy (some 
coarse), light gray- 
ish brown, medium, 
very glauconitic 
(some coarse); 
vague spherules; few 
beds of sandstone, 
dolomitic, medium, 
fight grayish brown, 
well cemented, poor- 
ly sorted, glauconitic 23 2200 

Sandstone, slightly 
dolomitic, white, me- 
dium, poorly sorted, 
friable; few streaks 
of sandstone, dolo- 
mitic, light brown, 
white, pale pink, me- 
dium to fine, well ce- 
mented 106 2306 

EAU CLAIRE FORMATION 

Sandstone, slightly 
dolomitic, light gray, 
fine, friable, glaucon- 
itic; some dark gray 
shale partings; little 
dolomite, silty, light 



gray to light pinkish 

gray, very fine .... 34 2340 

Sandstone, silty, light 
gray to pink, very 
fine to fine, friable, 
glauconitic, fossilifer- 
ous; shale, silty, 
green, gray, weak to 
brittle 38 2378 

Siltstone, grayish 
orange to light gray, 
coarse, compact, 
glauconitic, micace- 
ous; shale, greenish 
gray, brittle, micace- 
ous 72 2450 

Interbedded siltstone, as 
above, and shale, 
greenish gray, red, 
brittle, micaceous . . 38 2488 

Sandstone, silty, dolo- 
mitic, light gray to 
grayish orange, very 
fine, compact, glau- 
conitic, micaceous, 
fossiliferous; a little 
conglomerate of 
dolomite, yellow, 
pink, white, coarse, 
glauconitic; fossil 
fragments; some sand 27 2515 

Sandstone, as above; 
grades to coarse silt- 
stone; shale, silty, 
greenish gray, brittle, 
micaceous; conglo- 
merate, as above . . 35 2550 

Sandstone, dolomitic, 
light gray to light 
brown, fine, friable to 
compact, fossilifer- 
ous, pyritic, partly 
sooty; some shale, 
silty, greenish gray, 
brittle, micaceous . . 50 2600 

MT. SIMON SANDSTONE 

Sandstone, white to 

light gray, medium 

to fine, poorly sorted, 

friable, rounded, 

slightly sooty 44 2644 

Sandstone, white, med- 
ium, poorly sorted, 

rounded, friable; 

some very coarse 

grains 76 2720 

Sandstone, pink, med- 
ium, poorly sorted, 

friable, hematitic; 

some pale yellow 

grains; shale, red, 

green 90 2810 



53 



Sandstone, silty, argil- 
laceous, pink, pale yel- 
low, medium to fine, 
very poorly sorted, 
friable; little shale, 
silty, red, very mica- 
ceous, brittle 40 2850 

Sandstone, pink to red, 
medium to coarse, fri- 
able, poorly sorted, 
partly hematitic; some 
pale yellow grains... 100 2950 

Sandstone, white, pale 
yellowish gray, med- 
ium, poorly sorted, 
rounded to subangu- 
lar, friable, clean, po- 
rous; some broken 
grains 50 3000 

Sandstone, white, fine, 
moderate sorting, 
subrounded, friable 
to well cemented by 
silica 190 3190 

vSandstone, white, pink, 
fine (some medium), 
subrounded, friable 
to slightly friable, 
some red ferruginous 
bands 220 3410 

Sandstone, red, pink, 
little white, medium, 
subangular, friable to 
slightly friable, poorly 
sorted, hematitic ... 190 3600 

Sandstone, white, pink, 
fine to medium, sub- 
angular, moderately 
sorted, slightly fri- 
able; some beds hard, 
well cemented by 
silica, low porosity 75 3675 

Sandstone, pink, fine to 
medium, moderately 
sorted, slightly fri- 
able, low porosity. . . 45 3720 

Sandstone, pink, med- 
ium, subrounded, 
moderately sorted, 
friable, porous 30 3750 

Sandstone, white, pink, 
red, medium to fine, 
rounded, friable; soft 
white to pinkish clay 
— possibly drilling 
mud 



Sandstone, arkosic, red, 
hematitic; quartz 
fragments, as above, 
but increased feld- 
spar 

PRECAMBRIAN 

Granodiorite, c o a r* s e , 
dark; pink and red 
feldspar, clear quartz, 
considerable biotite . 



15 3855 



8 3863 
(total depth) 



2. CITY OF KEWANEE NO. 4 

Partial sample study log of the City of Kewa- 
nee No. 4 well, sec. 4, T. 14 N., R. 5 E., Henry 
County, Illinois. Total depth 2501 feet. Elevation 
843 feet. Illinois Geological Survey sample set 
52353. Drilled by Varner Well Company. De- 
scribed by J. E. Brueckmann, September 1965. 



Depth 

(ft) 



Sandstone, arkosic, 
coarse, red, pink, 
rounded and angular 
quartz fragments; 
very little feldspar . . 



75 3825 



15 3840 



Thick- 
ness 

(/O 
ORDOVICIAN SYSTEM 

PRAIRIE DU CHIEN GROUP 

SHAKOPEE DOLOMITE (165') 
Dolomite, light brown- 
ish gray, pink, extra 

fine, slightly sandy in 

part; little chert, 

white, clear, partly 

oolitic 65 

Shale, green, weak, 

slightly sandy in part; 

little dolomite and 

chert 

Dolomite, buff, light 

brownish gray, extra 

fine, slightly sandy in 

part; little chert . . . 
Dolomite, grayish red, 

little gray to light 

brownish gray, extra 

finely crystalline . . . 
Dolomite, light brown 

to buff, extra fine to 

very fine, slightly 

sandy in part 

NEW RICHMOND SANDSTONE (65') 
Sandstone, fine to 

coarse, incoherent; 

dolomite, light brown- 
ish gray, extra fine, 

partly silty and clay- 
ey (buff); trace of 

white chert .... 
Dolomite, extra fine, 

light gray to white; 

trace of sand; trace 

of white chert 15 

Sandstone, medium to 

coarse, dolomitic, in- 



1535 



10 1545 



45 1590 



10 1600 



35 1635 



30 1665 



1680 



54 



coherent; dolomite as 

above 20 1700 

ONEOTA DOLOMITE (170') 

Dolomite, white, light 
yellowish gray, partly 
fine to medium, little 
coarse, very cherty 
(light gray to yellow- 
ish gray) 25 1725 

Dolomite, as above; 

trace of chert 70 1795 

Dolomite, light brown- 
ish gray, fine to 
coarse; little chert . 20 1815 

Dolomite, as above, 

cherty 35 1850 

Dolomite, as above, 
pink, slightly glau- 
conitic 20 1870 

3. VILLAGE OF 
NORTH HENDERSON NO. 1 

Partial sample study log of the Village of North 
Henderson No. 1 well, sec. 26, T. 13 N., R. 1 W., 
Mercer County, Illinois. Total depth 710 feet. 
Elevation 760 feet. Illinois Geological Survey 
sample set 30260. Drilled by Peerless Service 
Company. Described by G. H. Emrich, 1957. 

Thick- 
ness Depth 
(ft) (ft) 
DEVONIAN SYSTEM 

CEDAR VALLEY FORMATION 
Dolomite, light brown 
to grayish brown, 
very fine to fine, cry- 
stalline 10 335 

No sample 5 340 

Dolomite, silty, light 
brown to huffish 
gray, very fine to 
fine, crystalline .... 20 360 
Dolomite, very argil- 
laceous, silty, light 
huffish gray to huf- 
fish gray, very fine 40 400 
Dolomite, calcareous, 
brown, very fine to 

fine, crystalline 5 405 

WAPSIPINICON FORMATION 
Limestone, slightly 
dolomitic, slightly 
silty, buff to brown- 
ish buff, very fine to 
fine, crystalline .... 25 430 
Limestone, slightly 
dolomitic, silty, gray- 
ish brown to brown- 
ish gray, very fine, 

crystalline 35 465 

Limestone, fight gray to 
buff, very fine to ex- 
tra fine 10 475 



Dolomite, slightly 
silty, buff to brown- 
ish gray, very fine to 

fine, crystalfine 20 495 

SILURIAN SYSTEM 

Dolomite, white to light 
gray, little gray, very 
fine to fine, crystal- 
line 5 500 

No sample 5 505 

Dolomite, light gray, 
little gray, very fine 
to medium, little 
coarse, crystalline . . 35 540 

Dolomite, light gray, 
little gray, very fine 
to fine, little medium, 
crystalline 25 565 

Dolomite, light huffish 
gray to light gray, 
very fine to fine, crys- 
talline 35 600 

Dolomite, slightly silty, 
light buff to gray, 
very fine to fine, little 
medium, crystalline. 20 620 

Dolomite, light buff to 
grayish buff, very fine 
to medium, crystal- 
line 10 630 

Dolomite, slightly silty, 
light grayish buff to 
gray, very fine to 
fine, crystalline .... 10 640 

4. MARGARET BLOOMER NO. 1 

Partial sample study log of the Margaret 
Bloomer No. 1 well, sec. 16, T. 9 N., R. 3 E.. 
Knox County, Illinois. Total depth 619 feet. 
Elevation 630 feet. Illinois Geological Survey 
sample set 9840. Drilled by Larson and Swan- 
son. Adapted from study by M. P. Meyer, 1943. 

Thick- 
ness Depth 
(ft) (ft) 

MISSISSIPPIAN SYSTEM 

KEOKUK-BURLINGTON LIMESTONE 

Chert, dolomitic, cal- 
careous at base, 
slightly glauconitic, 
light gray 12 200 

Dolomite, very cherty, 
calcareous at base, 
silty, light gray to 
light buff, very fine 15 215 

Limestone, very cherty, 
dolomitic, glauconi- 
tic, silty, light gray, 
medium to coarse, 
crinoidal 15 230 



55 



Limestone, very cherty, 
dolomitic, light gray 
to light buff, medium 
to coarse, crinoidal . 10 240 

Dolomite, very cherty, 
calcareous, glauconi- 
tic, light buff to light 
gray, very fine 20 260 

Limestone, very cherty, 
dolomitic, light buff 
to light gray, medium 
to coarse 20 280 

Limestone, cherty, 
dolomitic, light gray, 
fine to medium .... 30 310 
MISSISSIPPIAN AND DEVONIAN SYSTEMS 
NEW ALBANY SHALE GROUP 

Shale, dolomitic, green, 
brittle; little sand- 
stone, dolomitic, light 
gray, very fine, com- 
pact at top 15 325 

Shale, slightly dolomi- 
tic, light gray; little 
siltstone, dolomitic, 
light gray, compact . 55 380 

Shale, slightly dolomi- 
tic, light gray and 
brown variegated; 
spores; little siltstone 50 430 

Shale, light gray, weak 10 440 

Shale, brown; spores . . 30 470 

Shale, light gray; trace 

siltstone 15 485 

Shale, dark brown, 

brittle; spores 34 519 

Shale, light gray, weak, 

pyritic 33 552 

5. VILLAGE OF WOODHULL NO. 2 
Partial sample study log of the Village of 
Woodhull No. 2 well, sec. 30, T. 14 N., R. 2 E., 
Henry County, Illinois. Total depth 1369 feet. 
Elevation 824 feet. Illinois Geological Survey 
sample set 554. Drilled by J. P. Miller Well 
Company. Studied by L. E. Workman, 1925. 
Description published by Wanless (1929, p. 187). 

Thick- 



PENNSYLVANIAN SYSTEM 

Shale, silty, slightly 
calcareous or noncal- 
c a r e o u s , medium 
gray, micaceous, very 

soft 

Shale, calcareous, dark 
gray to black, non- 
carbonaceous, n o n - 
laminated, tough or 

soft 

Shale, noncalcareous, 



ness 
{ft) 



Depth 
iff) 



45 145 



15 160 



medium gray, soft; 

with coal 5 165 

Underclay, light gray, 
soft, micaceous; con- 
tains many pieces of 
yellowish brown, 
granular, fine- 
grained limestone . . 10 175 

Underclay, silty, light 

gray, soft, micaceous 15 190 

Shale, dark gray, soft; 
some black lamin- 
ated, brittle 5 195 

Shale, silty, light yel- 
lowish gray, brown- 
ish gray, and dark 
gray, soft; with coal 
at base 30 225 

Shale, silty, dark gray 
to black, micaceous; 
with streaks of light 
gray, argillaceous 
siltstone 25 250 

Underclay, silty, med- 
ium brownish gray, 
soft, micaceous; coal, 
shaly, impure, dull; 
siltstone, argillace- 
ous, light gray; and 
dolomite, argillace- 
ous, brown, tough . . 15 265 

Shale, dark and light 
gray, micaceous, 
poorly laminated; lo- 
cally calcareous and 
concretionary 65 330 

Sandstone, calcareous, 
medium gray, pyri- 
tic; grains fine to me- 
dium, poorly sorted. 5 335 

Shale, dark and light 

gray 5 340 

Sandstone, calcareous, 
well cemented, dense, 
pyritic 5 345 

Shale, silty, dark and 
medium gray, non- 
laminated 15 360 

Sandstone, dolomitic, 
pyritic; grains are 
fine, clear, angular or 
rounded, frosted ... 5 365 

6. VILLAGE OF CARBON CLIFF NO. 1 

Sample study log of the Village of Carbon 
Cliff No. 1 well, sec. 4, T. 17 N., R. 1 E., Rock 
Island County, Illinois. Total depth 1105 feet. 
Elevation 575 feet. Drilled by Cliff Neely, 1951. 
Studied by D. W. Baird. Thick- 

QUARTERARY SYSTEM ness Depth 

PLEISTOCENE SERIES (//) (//) 

"Sand and gravel" ... 90 90 



56 



SILURIAN SYSTEM 

Dolomite 350 440 

ORDOVICIAN SYSTEM 
MAQUOKETA GROUP 

Shale and dolomite ... 215 655 
GALENA AND PLATTEVILLE GROUPS 

Dolomite 330 985 

GLENWOOD-ST. PETER SANDSTONE 
Sandstone, some shale 40 1025 
Sandstone 75 1100 

7. CITY OF ABINGDON NO. 2 

Sample study log of the City of Abingdon 
No. 2 well, sec. 33, T. 10 N., R. 1 E., Knox 
County, Illinois. Total depth 2583 feet. Eleva- 
tion 747.5 feet. Illinois Geological Survey sample 
set 703. Drilled by Thorpe Bros. Studied by L. 
E. Workman, 1927. 

Thick- 
ness Depth 
(/O (ft) 

QUARTERNARY SYSTEM 
PLEISTOCENE SERIES 

Drift 35 35 

PENNSYLVANL\N SYSTEM 

Shale, limestone, and 

sandstone 155 190 

MISSISSIPPIAN SYSTEM 

Limestone 120 310 

MISSISSIPPIAN and DEVONIAN SYSTEMS 

Shale 240 550 

DEVONIAN SYSTEM 

Limestone, shaly .... 60 610 

Limestone 20 630 

SILURIAN SYSTEM 

Dolomite 90 720 

ORDOVICIAN SYSTEM 
MAQUOKETA GROUP 

Shale and dolomite ... 180 900 
GALENA AND PLATTEVILLE GROUPS 

Dolomite 310 1210 

GLENWOOD-ST. PETER SANDSTONE 
Sandstone, some shale 

at base 100 1310 

Sandstone 100 1410 

Sandstone, shale, and 

chert 5 1415 

SHAKOPEE DOLOMITE 

Dolomite 255 1670 

NEW RICHMOND SANDSTONE 
Sandstone and dolo- 
mite 60 1730 

ONEOTA DOLOMITE 

Dolomite 250 1980 

CAMBRIAN SYSTEM 

EMINENCE-POTOSI DOLOMITE 
Dolomite 260 2240 



FRANCONIA FORMATION 

Dolomite and sand- 
stone 230 2470 

IRONTON-GALESVILLE SANDSTONE 

Sandstone 110 2580 

EAU CLAIRE FORMATION 

Dolomite 2 2582 

8. CITY OF ALEDO NO. 1 
Sample study log of the City of Aledo No. 1, 
sec. 17, T. 14 N., R. 3 W., Mercer County, 
Illinois. Total depth 3114 feet. Elevation 739 
feet. Drilled by George Dickson. Drillers log 
interpreted by T. E. Savage, 1889. 

Thick- 
ness Depth 
(ft) (ft) 
QUARTERNARY SYSTEM 
PLEISTOCENE SERIES 

"Clay" 110 110 

PENNSYLVANIAN SYSTEM 

"Shale and coal" 52 162 

MISSISSIPPL\N and DEVONIAN SYSTEMS 

"Shale" 138 300 

DEVONIAN SYSTEM 

Limestone 146 446 

SILURIAN SYSTEM 

Dolomite 146 592 

ORDOVICIAN SYSTEM 

MAQUOKETA GROUP 

Shale and dolomite . . 215 807 
GALENA AND PLATTEVILLE GROUPS 
Dolomite and little 

shale 313 1120 

GLENWOOD-ST. PETER SANDSTONE 
Sandstone, dolomite, 

shale 60 1180 

Sandstone 60 1240 

SHAKOPEE DOLOMITE 

Dolomite 125 1365 

NEW RICHMOND SANDSTONE 

Sandstone 105 1470 

ONEOTA DOLOMITE 

Dolomite; sandstone . . 295 1765 
CAMBRIAN SYSTEM 

EMINENCE-POTOSI DOLOMITE 

Dolomite 195 1960 

FRANCONIA FORMATION 
Shale; dolomite; sand- 
stone 205 2165 

IRONTON-GALESVILLE SANDSTONE 

Sandstone 150 2315 

EAU CLAIRE FORMATION 

Shale 142 2457 

EAU CLAIRE FORMATION AND MT. 
SIMON SANDSTONE 

Sandstone 657 3114 

(total depth) 



Illinois State Geological Survey Report of Investigations 221 
56 p., 14 figs., 3 tables, 1968 



(43668—8-67) 
,14